SUSE Manager officially supports maintained clients (== clients running an OS under SUSE maintenance) only.
However, for bringing unmaintained clients (SLES 10 SP2 for example) to a maintained state (SLES 10 SP4 for example), we will help if this migration is guided by a SUSE Sales Engineer or a SUSE Partner.

For SLES9, that's a completely different story since SUSE Manager was never ported to SLES9. Technically, it's probably possible but will require a fair amount of work.