The truth is, 9MM has been adopted for much the same reason as 5.56MM. It's light, has a little less recoil, and you can carry a whole lot of it. Effectiveness is not really why it was adopted.
NOTHING penetrates brush, that's an old myth. The 230 grain 45ACP ball ammo penetrates farther through most doors, walls, clothes, and flesh, than 115 grain 9MM.
Stopping power is not as important in military weapons? I can assure you most soldiers will strongly disagree with that statement. Like any combat, you want the guy to go down quickly, with as few shots as possible. The NUMBER ONE COMPLAINT with 5.56 NATO is FAILURE TO STOP. The same applies to 9MM. You know why U.S. soldiers like to pick up AK's? Because 7.62 stops better and faster than 5.56 NATO. When your opponent is shooting at you the first thing you want to do is STOP him from shooting at you. And you sure as Hell don't want to have to shoot him several times to make him stop, either.
By the way, "blah, blah, blah" is just a chump's way of saying he can't refute the text he replaces with "blah, blah, blah." If that crap is all you've got, I've got no more time for you.