I’ve got Max 9 and was wondering if it is possible to export a model so that one will be able to view it as a 3D PDF.  Or is there any other way that I can export so that a layman will be able to view the model in 3D and not just as a rendering/screenshot?

For PDF, there is a thread about that already.
As an alternative, there is Autodesk’s own DWF format. The client will need to download the free DWF Viewer from the Autodesk site. It’s actually called Design Review now, not DWF Viewer, but the same thing.