If it has the towing package it will have a hitch on it. Unless you're in Canada, which, I understand, all CX9s were set up for adding the hitch.
To tell if you have the extra cooling, look at the two radiator fans. If they both have the silver control module on the fan frame, like in vike's center photo, you have it. Non towing like mine only has one on the drivers side fan.
Also, take the rear cargo bins out and see if the trailer light connector is there. It taps into the left side taillight harness, I believe, and will be a square connector.