The 9100 is basically a rebadged 8500, supporting the same DirectX 8.0 features that the 8500 did.
The 9600 Pro, although more money, will provide performance similar (but not quite equal to) the 9500 Pro.
If you can afford the 9600 Pro, grab it. If you want to wait a little longer, pick up a used 9500 Pro or 9700 Pro off E-Bay, flash the card with Warp11's Overclocking BIOS and enjoy your games