Critical Duty is more penetration focused, I would worry about its expansion capabilities from shorter barrels. Pretty sure it will still work to put someone down, but it isn't an optimal pairing for the gun.
Not a fan of Critical Defense, I would rather recommend a loading that uses the Hornady XTP bullet.
However, I carry 124 grn standard pressure Federal HST in my Kahr PM9, I'm an obsessive over-analyzer type and this is the round that I have come to favor. There are many other rounds that could work, but Gold Dots, for example, have a longer overall length than the HSTs and were possibly to blame for the few hangups I've had in my PM9 while HSTs were flawless.