If you are going by muzzle energy, a .17 beats the .45.
But in the real world, that big fat slow .45 makes a big damn hole in bad guys, and dumps all of it’s energy into him. The 9mm hardball zips right through, and leaves most of its energy in the next wall.
Now, if you are upping the ante to 9mm +P hollowpoints, that is a different issue, and a solution forbidden to soldiers.
Yep. Learned that from an instructor at USN gunnery school who was probably alive when the 1911 hit the market.
Hey !.......I still have that letter from the DOD authorizing me too use hollow point ammo in anti terrorist low intensity conflicts aka LIC Missions !!
Of course I keep it in a hermetically sealed , stainless steel box buried under the arc of the covenant for safety just in case they want a copy !