Early Morning IAH Rental Return?

Renting a car for the week in Houston and I have a 7:15 flight home on New Year’s Day. I just realized the airport website says the car rental shuttle doesn’t start running until 7AM which seems crazy at such a busy airport! Is there any other way to get back to the terminal when I return the car? Or do I just need to return it the day before and uber to the airport the next morning? Thanks!