Um, yea... a 147grn fmj 9mm would probably have no problem penetrating through a deer. I mean, if you don't think so I'd guess you really don't know how sectional density works for non expanding projectiles. Same reason .357 with hardcast has been successful on deer. Doesn't take much energy to penetrate far when bullets aren't expanding. So as far as deer are concerned, they won't know much difference. They are not hard to kill.
You probably can't come up with any good reason why the 10mm is not suitable for deer, you should probably just quit wasting your time.
A 147gr 9mm FMJ can penetrate through a deer, that is why I said it. I was using your flawed logic to sarcastically say it must be an adequate deer round then. I will try and explain things further next time so you can keep up.