There are a number of items to delete.
So drag all the following relevant items to trash, then empty it.
1) the applications folder itself (not the Mac OS9 Applications folder, but the one relating to the program to be deleted)
2) Preference files from the system folder, that relate to the program in question.
3) Extensions that relate to the program
(System folder > extensions) or via extensions manager control panel.
4) Installer logs for the program in question.
These are often in the first level of the Start up system disk, or system folder. Simply use finder “find” files function to loacte any outstanding bits of stuff for the trash.
5) Incertain specialised cases there may also be a Control Panel relating to the program, these are to be found in the system folder >> Control panels folder.
Thats the lot.