If you have a modern Mac, attach a CD burner (or use the internal one if available), right click on the image file (e.g. the .iso or .toast) and select the burning command (I don‘t remember the exact command name).
I've heard modern Mac OS doesn't do classic mac os bootable cds any more? I don't use current macs.
What I don't know how to do, is to make bootable images. Is their a setting in Toast that I am missing?
The problem is that a huge number of online images are have not been copied in a way that preserves the bootability. More are bad than good, so it doesn't really matter.
Old Toast versions had a "bootable" checkbook. Newer versions just did it automatically.
Something I'd try is mounting the image on the OS 9 computer and telling Toast to make a CD from the mounted Volume.
Burning a bootable CD that way burns the CD driver from the running OS onto the CD, so disks burned that way will contain the 9.2 driver and won't boot 68k macs.
A good iso image should contain its original driver and boot whatever the original disk booted.