It appears that there have been a few different designs of the Archos G9 case. I have seen some pictures where there are screws under each of the rubber feet and others where there are none - mine doesn't have them, even though I once thought it did!
There is also no sign of a screw under the kickstand on mine.
In order to release all the clamps around the body of the tablet that hold the two parts together, you will need some strong, thin tools. Guitar plectrums have been recommended here - I would recommend getting some very strong ones made of fibreglass or carbon fibre. Don't use metal ones, or you will damage the plastic casing.
I picked up a kit on e-bay
that does the job quite well.