KT loaded with 9 shots of 124grn. +p federal HST/Gold Dot
642/442 laoded with 5 rounds of 135 grn. +P short Barrel GD.
Your choice, but I would ALMOST sway toward the KT once proven reliable ,if you think your given carry scenario would warrant the larger amount of rounds.
I have a KT P11 and a 442 and they are virtually the same size, with the KT loaded weighing just a bit heavier, so a PF9 will be a bit less.
Most days for me its the M&P .357sig c
6 of 1, 1/2 dozen of another.