I drove a 9650 STS for a few minutes at a field day. The Deere rep. said the 9750 had more HP, a bigger bin, and heavier final drives. Other wise he said they were the same machine.
Our dealer said the only differance between the two machines is a hopper topper and the computer chip that tells the engine how much power to make. The price differance between them was about $25,000 Canadian dollars.