Norton cannot remove the virus from the documents because CDs are read-only, so the files on the CD cannot be modified without first copying them off the CD.
You need to copy all the files off of the CD, clean the files of the virus, then burn them back to a different CD.
I don't understand what this means. OS 9 and OS X are mutually exclusive operating systems... what do you mean by "OS 9 unreadable on OS X?"Why has Apple decided to make OS 9 unreadable on OS X?