As far as I know about OptiSystem versions, OptiSystem 9 had some major changes in terms of the added components and so on from the former versions. So I think here “simulation files for optisystem 9+” means the components used in these simulations can be found in versions 9 and newer, and it does not necessarily mean the files can be run by version 9. However, I believe it should have been mentioned in a more clear way.