Then clicked on the ‘Get It’ button which seems to take you to the a download page, but for older versions. I did trying the ‘Factory’’ 1-Click version but recieved a message when installation stated of ‘The install link or file you opened does not contain instructions for this version of openSUSE’
Use software.opensuse.org: Download openSUSE 12.3, search for Banshee and you will be presented with the available versions. Mind, don’t install packages for other versions than the one you’re running.
On 13.1: wait a bit, the repos for it will be available after release (and build of the packages).
I checked, there’s simply no package for openSUSE (yet). Plus, I visited the banshee page, 2.9.0 is a development release. Hence, the only way to get it, is to compile it yourself.
EDIT: I gave it a try, couldn’t meet all the requirements. I don’t feel like adding GNOME UNSTABLE repos just to test. My 2 cents: wait until Banshee 2.9.0 is declared stable, it should be in the repos in no time after that.