Well, yeah, they can.
Certain 9500's were built on the 9700 PCB's. The 9500 core is the same as the 9700 core, except it has half the pipelines disabled.
If you enable the pipelines, then you basically have a 9700, although the clock speeds might not be up there, and there might be artifacting due to bad pipelines.
But it only works for certain 9500's (with red PCB's, Sapphire I believe)