Bindery

My wife and I are renting a car at the Brussels airport and will drive across France then into Germany ending at Boppard for 3 nights.
My plan is to leave Boppard Thursday morning and drive to Leuven stay there Thursday night and then drive to Brussels airport early in the morning, drop off the car and catch our 9:10am flight.
The Hertz counter opens at 6:30am so I believe dropping off the car at 6:30am would give us enough time to check in and catch the flight.
Or
Should we drive and drop off the car Thursday and take a train to either Brussels or Leuven and spend the night there, then take the train back to the airport in the morning.

Any thoughts and suggestions would be appreciated.

Odin

You can do either. Dropping the car off at 06.30am is plenty of time for a 09.10am flight and presumably you would check in online anyway. Be aware that there is often alot of traffic around BRU airport during rush hour, I've been caught in it many many times.
But I've also dropped the car off the night before and stayed either at the airport or in the city and have taken the train to/from the airport. It's probably less stress to take this option.