Sorry for stating you would get rental agreement, I meant you would get updated reservation which is what you got.
Once you get to airport and use the kiosk, it prints our the rental agreement. Once you pick out your car in whatever class you rented, give the tag that's in the car, along with your driver's license & credit card to the exit gate rep. It's quick and easy. I've done online checkin and just walked out to garage and picked car, but still received the actual agreement from the exit gate rep.