Hiya mate, it shouldn`t boot from cd, it was never designed that way, same as any other cd based amiga os.
You would have to buy an SX-1 expansion for it ir similair, to provide expansion for mem, then install a harddrive to allow acces of the start up sequence.
You could burn a start up sequence on to a cd, and set it up assigns as you would an old cdtv disk on kick 1.3.
So yes you could run os3.9 on a cd32, but you need expanded mem and a hard drive, or create youre own version of os3.9 with a start up sequence with assigns for the directorys etc.
Cheers the Muckster :inquisitive: