lol No they didn't otherwise it wouldn't have needed a "patch" to make it DX11. It's a DX9 based game which ever way you want to look at it.
...and will never fully utilize Dx11.

This is nonsense.
DX9, 10, 11... are APIS. Microsoft ones. Cryengine works in PC, XBox, and ps3. Ps3 does not use DX. The api is configured to use the end API they desire. If they want they could have used instead of DX... OpenGL.
So it is not a DX9 api. The only fact is that working first with DX9 Api you have results in two platforms, at least(PC and XBOX)... so it is not DX9. The real question is:
Features that are only available in DX11 cards. as tesselation... Cryengine 3 api is able to use them now?