About model and data exchange with 3rd party solutions: Revit, Solibri, dRofus, Bluebeam, structural analysis solutions, and IFC, BCF and DXF/DWG-based exchange, etc.
You need an Add-on, a plugin, to import 3DS files. Later versions are found under Goodies in the Help menu, but for AC9 and previous, I think you'll have to talk to your reseller to get it.
3) IMPORT (not open) your .3ds file in SketchUp and save as a SketchUp file (You may need to archive it to an earlier version for ArchiCAD 9).
4) Open the SketchUp file in ArchiCAD 9; you'll get a window that tells you what to do & pretty much takes it from there for you. It can be a long process, depending on how large your .3ds file is, but this should then convert everything so that you can then work with it as an ArchiCAD 9 file.