decrypt data-partition in twrp
My data-partition is encrypted with a 3x3 pattern and TWRP can't
  decrypt it


This can be solved by considering the 3x3 grid as the numbers on the keypad. For Example, consider a pattern that looks like the uppercase L character.

↓ o o  |  1 2 3
↓ o o  |  4 5 6
↓ → →  |  7 8 9


here, your password would be 14789