Multiple versions and variants of OS-9 are included. There are images for NitrOS-9 on CoCo and Dragon, several ports of OS-9/6809, OS-9/68K 2.4 for X68000, and OS-9000/x86 6.1.
Ran it on a 32k/64k Color Computer.
So did I actually. Was also on an OS-9000 based project for a short while.