me personally if i were worried about penetrating body armor, if i wanted a 9mm that would penetrate i would get .357sig, there are MANY guns out there chambered in it from the subcompact Glock 33 on up to a fullsize G31 or Hk usp-357 or similar. or if you want a little bigger punch and can handle carrying it, get a 10mm, has plenty of velocity and would probably penetrate (im guessing?) and its a .40 caliber bullet for the punch. plus with 10mm i dont care if it doesnt penetrate, most likely he will go down or at the very least make him stagger and/or lose his balance. this will allow you to make your next shot carefully aimed at a more critical area.
and to note, if you are wanting it to penetrate body armor, you need to carry FMJ instead of JHP.