Oh dear, I'm afraid this isn't going to work. MacBinary encoding, which is the only method of transfer which will retain the resource fork and Finder meta data, is not supported with sync or with SFTP.
Since I assume it's unlikely that anyone will be modifying OS9 files in 2011, you could create an archive of them in the Finder and store that file on the server as a backup. Then you could exclude the OS9 files from the sync.
If you have lots of OS9 files scattered around then I'm at a loss for a solution.