If you get to pick your own ammo (which is unlikely), go with the Cor-bon 115-grain +P, the Federal 9BPLE 115-grain +P+, or the Federal 9BP 115-grain HP. If you're stuck with a department-issued 147-grain load, you're fucked. Carry their load 'til you're off probation, then buy one of the above loads and carry it instead. A letter in your file for non-approved ammo is better than getting dead. Those loads I listed will perform as well against people as most .45 loads. The 147-grain loads flat suck.
Find out if your department has an alternate weapons policy. My department issues Glock 9's and 45's, but I can carry a personally-owned .40 if I wish. Lots of departments are adopting this approach.
Good luck!
BTW, the stuff about SEAL's using 9mm because it won't go through walls in CQB scenarios is a bunch of shite. I don't doubt that's what the TV said, but once again, they got it wrong. 9mm ball and almost all factory hollowpoints will sizzle through multiple walls of common residential or business construction. They use it because it is the NATO standard and they can get it anywhere in the world.