I've managed to find a way so that the bookmarks are identical in both OS 9 & X. So if I ever have to switch to the other OS, my bookmarks are always up to date.
In OS 9, your bookmarks are stored in in System Folder/Preferences/Explorer/Favorites.html.
In OS X, your bookmarks are stored in User/Library/Preferences/Explorer/Favorites.html.
Now all you have to do is make an alias of your bookmarks from OS 9, in your OS X version. Or vice versa.
Thats it. Works great!