Hello. I have one 1911 chambered for 9mm, an STI Trojan. It's a 6" long slide. It's primary diet is warmish handloads and +P factory ammunition. The one-piece feed ramp allows for a very supported chamber. I'm not sure what 1911 you're using so I don't know if you have a fully supported chamber or not.
Most conventional two-piece feed systems don't have quite as much chamber support, but most have plenty to handle +P or any sane handload.
The 1911 is a pretty stout pistol to begin with and certainly larger than necessary for the 9x19mm.
It's generally true that the hotter the load, the more rapid the increase in wear, but I suspect it'll take thousands upon thousands of shots to see this to any meaningful degree. If the standard velocity 9mm loads are "slow" with your present recoil spring, I suspect that the +P rounds won't be and that they might compress the spring a tad more. If so, I think this would weaken the spring at a quicker rate. How noticeable this might be in real life, I cannot say as I 've never measured it.
If shooting +P worries you, you might just drop down a pound or so on your recoil spring so that the standard velocity ammo works suitably.
My 6" gun has a 10-lb recoil spring in it. It functions (feeds, ejects & extracts) fine with standard velocity ammo, but it seldom locks the slide back after the last shot. With +P, function remains fine and the slide locks back. As I shoot mostly warm loads in this gun, I've left it alone.
If the 1911 handles the lower pressure-but-higher-momentum .45 ACP as well as the .38 Super (which is about like +P 9mm in most versions) as well as the
.40 and 10mm, I'd think you can shoot scads of 9mm w/o concern.
Best.