Download SheepShaver and install any version of MacOS that does not require an MMU into it - I have MacOS 9.0.4 working, and the site seems to suggest this is the latest version supported. 9.2.2 certainly doesn't work. Use the Mac OS ROM Update 1.0 available for download from Apple for the ROM.
Do test before deployment. I use it under Intel, where the CPU is completely emulated, but YMMV on a PPC as it just virtualises the supporting hardware (s/be faster!).