Rennes Airport Hotels
There are no hotels at the Rennes Airport but there are many close by. The hotels nearest the Rennes Airport are in the town of Bruz. There is for example the Best Western Ker Lann, you can read reviews. One thing to know is that Bruz is on the opposite side of the airport from Rennes. So yes, it closer but if your plan is to visit Rennes then you might be better off to stay at a hotel in Rennes or even Saint Jacques de la Lande where the airport is located. Even if you won't have transportation, there is bus service running from Bruz to Rennes that serves the airport. The cost is €1.10 for a ticket good for an hour.
Here is a list of hotels within 6 miles of the Rennes Airport.