Please can you have a look at making the Canon 90D compatible with the Ronin-S.

I am happy to purchase a IR-controller but I want to know if any of the control features will work with the camera.

Hello Gareth, Ronin-S is compatible with Canon EOS 90D. It doesn't support IR control but you can use the MCC-B cable that comes with the package to control it. More details about the compatibility, you can check out this link