3x3::k:4097:4097:4097:5888:4624:4624:4624:3345:3858:2315:2315:2315:5888:4367:4367:4367:3345:3858:5386:4364:3341:5888:2574:2574:2574:3345:3858:5386:4364:3341:6404:5888:6404:0000:0000:0000:5386:4364:3341:0000:6404:0000:2835:5908:5141:0000:0000:0000:6404:5379:6404:2835:5908:5141:2824:4105:3333:3333:3333:5379:2835:5908:5141:2824:4105:4102:4102:4102:5379:2582:2582:2582:2824:4105:4103:4103:4103:5379:3586:3586:3586:

547896321
126753948
938214576
892167435
453982167
761435289
375621894
284579613
619348752

Prelims

a) 9(3) cage at R2C1 = {126/135/234}, no 7,8,9
b) 21(3) cage at R3C1 = {489/579/678}, no 1,2,3
c) 10(3) cage at R3C5 = {127/136/145/235}, no 8,9
d) 11(3) cage at R5C7 = {128/137/146/236/245}, no 9
e) 23(3) cage at R5C8 = {689}
f) 20(3) cage at R5C9 = {389/479/569/578}, no 1,2
g) 11(3) cage at R7C1 = {128/137/146/236/245}, no 9
h) 10(3) cage at R8C7 = {127/136/145/235}, no 8,9

1a. 45 rule on N23 1 outie R4C5 = 6
1b. 45 rule on N78 1 outie R6C5 = 3
1c. 6 in N2 only in R123C6, locked for C6
1d. 3 in N8 only in R789C4, locked for C4

2. 45 rule on N5 2 innies R5C46 = 11 = {29/47}

3. 45 rule on N1 3 innies R3C123 = 20 = {389/479/569/578}, no 1,2

4. 45 rule on N9 3 innies R7C789 = 21 = {489/579/678}, no 1,2,3

5. 45 rule on R1 3 innies R1C489 = 11 = {128/137/146/236/245}, no 9

6. 45 rule on R2 3 innies R2C489 = 19 = {289/379/469/478/568}, no 1

7. 45 rule on R8 3 innies R8C126 = 19 = {289/379/469/478/568}, no 1

8. 45 rule on R89 3 remaining outies R7C126 = 11 = {128/137/146/236/245}, no 9

9. Naked triple {689} in 23(3) cage at R5C8, locked for C8
9a. 45 rule on C8 3 innies R489C8 = 9 = {135/234}, 3 locked for C8
9b. 7 in C8 only in 13(3) cage at R1C8, locked for N3
9c. 13(3) cage = {157/247}

10. 45 rule on C9 3 innies R489C9 = 10 = {127/136/145/235}, no 8,9

11. 21(4) cage at R6C5 = {1389/2379/3459}, 9 locked for C6 and N8, clean-up: no 2 in R5C4 (step 2)

12. 45 rule on N3 3 innies R123C7 = 17
12a. Hidden killer pair 8,9 in R123C7 and 15(3) cage at R1C9 for N3, 15(3) and 17(3) cannot contain both of 8,9 -> 15(3) cage and R123C7 must each contain one of 8,9
12b. 20(3) cage at R5C9 = {479/569/578} (cannot be {389} which clashes with 15(3) cage), no 3
12c. R489C9 (step 10) = {127/136/235} (cannot be {145} which clashes with 20(3) cage), no 4
12d. 15(3) cage = {168/249/348} (cannot be {159} which clashes with 20(3) cage, cannot be {258} which clashes with 13(3) cage at R1C8, other combinations don’t contain 8 or 9), no 5
12e. Killer pair 1,4 in 13(3) cage and 15(3) cage, locked for N3

13. R123C7 = 17 (step 12) = {269/359/368}
13a. 45 rule on C7 (using R123C7) 3 remaining innies R489C7 = 17 = {179/278/458/467} (cannot be {269/359/368} which clash with R123C7), no 3

14. 11(3) cage at R5C7 = {128/137/146/245} (cannot be {236} which clashes with R123C7)
14a. 7,8 of {128/137} must be in R7C7 -> no 7,8 in R56C7
14b. 45 rule on N69 3 innies R4C789 = 12 = {138/147/237/345} (cannot be {129} which clashes with 11(3) cage), no 9
14c. 11(3) cage = {128/146/245} (cannot be {137} which clashes with R4C789), no 3,7
14d. 3 in N6 only in R4C89, locked for R4
14e. R4C789 contains 3 = {138/237/345}
14f. 8 of {138} must be in R4C7 -> no 1 in R4C7

15. 3 in C7 only in R123C7, locked for N3
15a. R123C7 (step 13) = {359/368}, no 2
15b. 3 in C9 only in R489C9 (step 12c) = {126/235}, no 7
15c. 7 in C9 only in 20(3) cage at R5C9 (step 12c) = {479/578}, no 6
15f. 7 in C7 only in R489C7 (step 13a) = {179/278/467}, no 5

16. 10(3) cage at R3C5 = {136/145/235} (cannot be {127} because R3C7 only contains 3,5,6), no 7
16a. R3C123 (step 3) = {389/479/578} (cannot be {569} which clashes with 10(3) cage), no 6
16b. 45 rule on R3 (using R3C123 = 20) 3 remaining innies R3C489 = 15 = {249/258/267} (cannot be {159/456} which clash with 10(3) cage, cannot be {168} = [816] which clashes with 15(3) cage at R1C9, CCC), no 1, 2 locked for R3
16c. 10(3) cage = {136/145}, 1 locked for N2
16d. 1 in R2 only in 9(3) cage at R2C1, locked for N1
16e. 9(3) cage at R2C1 = {126/135}, no 4
16f. 1 in R1 only in R1C89 -> R1C489 (step 5) = {128/146}, no 5,7
16g. 16(3) cage at R1C1 = {349/358/457} (cannot be {259/367} which clash with 9(3) cage at R2C1, cannot be {268} which clashes with R1C489), no 2,6
16h. 9(3) cage = {126} (hidden triple in N1), locked for R2

17. R2C489 (step 6) = {478} (only remaining combination), locked for R2
17a. 15(3) cage at R1C9 (step 12d) = {168/249}
17b. R2C9 = {48} -> no 4,8 in R13C9
17c. 1 of {168} must be in R1C9 -> no 6 in R1C9
17d. R1C9 = {12} -> no 2 in R3C9
17e. R1C489 (step 16f) = {128} (only remaining combination) -> R1C4 = 8
17f. R2C9 = 8 (hidden single in R2) -> R13C9 = 7 = [16], R1C8 = 2
17g. Naked triple {359} in R123C7, locked for C7 and N3
17h. Naked pair {47} in R23C8, 4 locked for C8
17i. Naked triple {235} in R489C9, locked for C9

18. 11(3) cage at R5C7 (step 14c) = {128/146}, 1 locked for C7 and N6
18a. R4C789 (step 14e) = {237/345}
18b. 4,7 only in R4C7 -> R4C7 = {47}

19. Naked triple {479} in R4C7 + R56C9, locked for N6
19a. Naked pair {68} in R56C8, locked for C8 and N6 -> R7C8 = 9
19b. Naked pair {12} in R56C7, locked for C7 and N6, R7C7 = 8 (cage sum)
19c. R7C789 (step 4) = {489} (only remaining combination) -> R7C9 = 4

19d. R4C789 = {345} (hidden triple in N6) -> R4C7 = 4, R4C89 = {35}, locked for R4

20. R8C7 = {67} -> 10(3) cage at R8C7 = {127/136} -> R8C8 = 1, R8C9 = {23}
20a. 5 in N9 only in 14(3) cage at R9C7, locked for R9

21. 23(4) cage at R1C4 = {2678/4568}, no 9
21a. R2C4 = {47} -> no 4,7 in R3C4
21b. 9 in N2 only in R12C5, locked for C5

22. 10(3) cage at R3C5 (step 16c) = {145} (only remaining combination) -> R3C7 = 5, R3C56 = {14}, 4 locked for R3 and N2 -> R23C4 = [72], R23C8 = [47], clean-up: no 4 in R5C6 (step 2)
22a. Naked pair {59} in R12C5, locked for C5 and N2 -> R12C6 = [63], R12C7 = [39], R12C5 = [95]

23. 9 in C6 only in 21(4) cage at R6C5 = {1389/3459} (cannot be {2379} which clashes with R5C6), no 2,7
23a. R7C6 = {15} -> no 1,5 in R89C6
23b. Killer pair 1,4 in R3C6 and 21(4) cage, locked for C6
23c. 7 in C6 only in R456C6, locked for N5

24. 13(3) cage at R7C3 = {157/256}, no 3, 5 locked for R7 -> R7C6 = 1, 13(3) cage = {256} -> R7C5 = 2, R7C34 = {56}, locked for R7
24a. R7C6 = 1 -> 21(4) cage at R6C5 (step 23) = {1389} (only remaining combination), 8 locked for C6 and N8
24b. R6C6 = 5 (hidden single in C6)
24c. Naked pair {37} in R7C12, locked for N7
24d. Naked pair {47} in R89C5, locked for C5 -> R3C56 = [14], R5C5 = 8 -> R56C8 = [68]

25. 6 in N4 only in R6C123
25a. 45 rule on N14 3 innies R6C123 = 14 = {167} (only possible combination), locked for R6 and N4 -> R56C9 = [79], R56C4 = [94]
25b. Naked triple {289} in R4C123, locked for N4
25c. Naked pair {89} in R34C1, locked for C1, R5C1 = 4 (cage sum)

26. 11(3) cage at R7C1 = {236} (only possible combination, cannot be {137} because 3,7 only in R7C1) -> R7C1 = 3, R89C1 = {26}, locked for C1 and N7, R7C34 = [56], R9C4 = 3, R9C89 = [52], R9C7 = 7 (cage sum)
26a. R5C3 = 3 -> R34C3 = 10 = [82]

and the rest is naked singles.

I'll rate my walkthrough at 1.25. I used a lot of combination analysis for the cages and hidden cages, and a CCC.

Maybe the slightly higher SS score is because of the derived hidden cage totals; it might have used a different way to get them.