no, you can still dual boot. You will need to install OS9 again, as the bootable version will not be on the Panther disk.
If you have an OS9 disk, just install it before or after your Panther install. If you need to pull OS9 from you restore disks, it will be a bit trickier. Someone can help you pull those files off or you can restore everything and then upgrade the OSX portion.