To install Mac OS off of a restore CD for a different model...
1) Insert the CD,
2) Navigate to Configurations --> Disk Images (I think)
3) Mount the disk image
4) Copy over the system folder from the disk image to your hard drive.
5) Bless the new system folder.
I used my old iMac's software restore CD to get OS 9 onto quite a few other computers, so I know it works. And I don't see any reason why it shound't work w/ OS 9.1 & a PBG4 CD.