After hours drop off

Hi everyone,

I am going for a trip to Kumamoto this weekend, and planning to rent a car from Enterprise or National.

I will be renting and dropping off at Kumamoto Airport. My return flight back to my home country is 0845am but the operating hours of the office is 0800am to 2200pm. Any idea if they would have a drop off box or like a afterhour service ?

Thank you guys !