What he said. The 22 needs to be able to be taken apart for cleaning. The 45 will be bigger and longer than necessary for the 9mm, but the extra volume CAN lead to better suppression on the 9mm (depends on the can design and other factors). It also depends on whether best sound suppression is your goal, or more compact size. Same thing goes for the 30-cal and 556...
I personally have a factory made 22 (SWR Spectre II), a Form1 homemade 30-cal that uses the Dead-Air KeyMo mount and Sandman changeable end caps, and a Form1 homemade 45-cal that uses the Liberty booster/piston or direct thread adapters (it can also use the Griffin booster and adapters). In my case, performance was more important than size, but I also used Ti for the build and am able to keep the size and weight manageable on the 45 can to use it for 9mm. And my 30 is stupid quiet with 300blk subs, dit’s great with 308, and takes the bite off 556 without too much blowback in my DI guns.
You WILL find that, like anything else in your safe, suppressors tend to start multiplying once you get one...