If you don't have dedicated partition for /home, I would recommend backing up /home, and reinstalling. Make sure you create a partition for home. In the future, this will allow you to simple rename your old /home/<user> directory, and reinstall without reformatting the /home partition.
I wouldn't recommend an upgrade. A lot has changed from 9.0 to the present. SuSE used KDE4 now. PackageKit, PolicyKit, Pulse Audio & NetworkManager were introduced. So much will have to be replaced, upgrading successfully practically amount to a reinstall anyway.