There's no such thing as an IHG C&P reservation. IHG C&P only exists in the booking process. At IHG, C&P is nothing more than you buying some points during the booking process. The actually booking is done using pure points by the last step.

If you check your reservation after you've made it, you will find it's purely a points reservation by that time.

And if you cancel a reservation you made with C&P, you get no cash back, you instead get the full points back. (The points purchase you do during a C&P reservation is not reversible.)

Having said all that, it's July 2018, and there are multiple IHG credit cards out there, and AFAIK it's only the legacy ($49 AF) IHG credit card that gives the 10% rebate, not any of the newer cards. So if you don't have the older $49 AF card, you won't likely get 10% back on either pure points or C&P reservations.