This is what I thought as well, but wanted to ask for opinions.
Since the XL isn't just a small pistol suppressor & with the Bullet size difference in 9MM vs. .223 I thought there may be a possibility.
I looked on YHM's website & didn't see any info on max pressures.
I was going to do the 22lr/223 thing as well, but after talking to MajMal, he said the same thing about the can being sealed and the 22lr being dirty. I was figuring on going with a .308 can before money got tight.
I'm currently in the process of waiting on my ordered YHM Phantom 7.62. It has the quick detach and can be used on 7.62 or 5.56 or even on 22LR. It is fairly large and it is heavier than some, but it is stainless with Inconel baffles and the price is right. I certainly think it offers a lot of performance and versatility for the price range.