Help with installing/licensing Creo9

Hi-  I've been using Onshape over the past few years.  I'm now in a school that uses Creo 8,  upgrading to 9 soon.  I thought Id install Creo 9 on a laptop so I can refresh my skills before launching into a classroom of expectant students.  I keep going round in circles trying to get a teachers installation to "work".  Can you point me in the right direction please?