Sorry, I don't have any experience with HiTec radios so I can't offer any specific information. I use a Futaba 6XAS computer radio and it features a couple custom mix settings that allow you to enter anything you want. It is simply a matter of telling the radio what the primary channel is (in this case elevator) and the secondary (the one affected by the movement of the primary - in this case the main aileron channel) and then set the mix percentage that you want. On Futaba radios you can choose a negative or posative percentage which determines if the mix causes the surfaces to move in the same direction or in opposite directions when the primary channel is moved. I guess the baseline requirement for your radio to be able to do this is you need to first be able to set up for flaperons and second, some way to add a custom mix.

Yes, the 9C should work nicely for this but there are cheaper radios out there with the same capabilities. The new 7C from Futaba should work (as well as the 6XAS) and although I haven't used any of the JR 6 channel radios I know they are fairly comparable to the units from Futaba so I would think you should be fine with a JR 6 channel (or more) computer radio as well.