I was curious about something and dug around to see if I could find anything regarding performance loss between DirectX 9.0c and something older.
Unfortunately the well is kind of dry here, but Splinter Cell: Chaos Theory provides a good place to look:
https://www.beyond3d.com/content/articles/88/
https://www.extremetech.com/computing/75570-benchmarking-splinter-cell-chaos-theory/3
The tl;dr, enabling all 9.0c features makes performance tank on GeForce 6. Most of it was due to HDR rendering.
