So with the recent turning of the calendar, I looked at my Tiger and OS 9 install discs and it occurred to me they're getting on in years and very far from invincible. Time to make backups, I thought. So I fired up my burning app of choice, Burn.app, and made quick copies thinking I was done. Unfortunately I got a nasty surprise when I went to boot my iBook with the OS 9 copy to fix Debian's notorious disappearing partitions bug and found it unbootable. The Tiger DVD copy booted fine. It was only the OS 9 CD that was blurgged.
Okay, I thought, there's something wrong with the way Burn copies OS 9 discs. I'll just fire up Disk Utility and do it that way. One burned disc later and, crap, that won't boot either. So after googling this a bit and filtering out forum posts responding to questions saying, "Google it!" it appears the only way to burn a bootable OS 9 disc is with Toast. I tried it with my ancient copy of Toast 4.1.1 (that was a good year) which still runs in 9.2.2 and can confirm it works. The procedure is simple. It just takes a quick read through of the documentation to get it. I did not investigate whether you can do this with an OS X copy of Toast.
I'm still a bit clueless as to why the earlier copies were unbootable. They both had the correct file systems and had the hidden Trash and Desktop Folders. So I don't know.
This vexes me. I'm terribly vexed.