what i mean is, boot into the RH9 installation.
i guess you may have the installation CDs. put the first one in and boot/reboot the computer. if you've set the bios to boot from CD first (boot sequence), then the install will start.
here, where you get the choices of desktop, server, workstation, custom or to upgrade an existing installation, choose upgrade.
make sure it isn't messing around with partitions.
don't choose to install any of the packages because otherwise you will lose any new packages from up2date
when you come to the boot loader section, go along as normal: select the default OS that you want- this will be preselected when grub loads on boot. then make sure all your OSs are on the list. install grub on the mbr.
when you finish, you should have your choices back!