The only option I really wanted but didn't have on the CX-9I bought was the tow hitch package. I've called the dealer & supposedly this option isn't even available to purchase aftermarket or after factory build through Mazda.I can find the hitch no problem, but what I'm not sure about it the radiator fan & "Heavy Duty Transmission Cooler" as spec'd on the MazdaUSA.com package details.

Any idea what type of radiator fan & tranny cooler I would need to install a class II trailer hitch?

Not sure on that, but before you put a hitch on there, look up in your owners manual information about towing or using trailers or anything. That'll tell you what you can and can't pull with your CX-9 without voiding your warranty.