I once wrote some experimental plugin for Gamestudio with DirectX 11. Just put the file besides the script and your game runs with DirectX 11.
Biggest drawback was that i was forced to do some offscreen rendering, then move the DirectX 11 render target to the CPU and back to DirectX 9.
So it was quite slow, also there is no easy way on how to use shaders with the system.

So it would be either slow or really restricted in how to use it.