Airbnb never knows when the guests have arrived or left. Check in and check out times are set by you. The Airbnb email suggesting they have checked out usually shows up in the late morning and is just a reminder to you that their stay ends today.
If you need the guests out by a certain time so cleaners can go in, you should remind them of that with a message the night before.
If your cleaners show up and the guests are not gone the cleaners should encourage them to leave ASAP and should notify you.
If you don't have cleaners and you will clean/turn over the room when you get home, then you can offer late check out as a courtesy. Some guests will be very happy that they can come back at 4 pm for their luggage, and others will check out at 9 am anyway.
Communicate with the guests, both your expectations and their plans.