Is the cannon MX922 compatible with iMac? Which printer is compatible with the iMac?

You really need to ask Canon that question. We are not Apple and it may take a while for another end user with the same printer model to see this.

Did you look at this Apple support article:

Update printer software on Mac - Apple Support

According to ths Canon support page:

https://www.usa.canon.com/internet/portal/us/home/support/details/printers/inkjet-multifunction/mx-series-inkjet/mx922?subtab=downloads-drivers

they released new drivers for the MX 922 on Oct 2020 that support up to the the latest version of macOS 11 "Big Sur."

Yes. According to this Apple document that model is AirPrint compatible: About AirPrint - Apple Support

It can be connected wirelessly to your iMac.