The beauty of Airbnb is the fact that every listing is personal. Asking for an early check-out and providing an early check-in could easily be part of your “brand” - you’ll be the early bird Airbnb.
(my brand is; soup nazi married to nicest guy you ever met Airbnb.)
That said, I think you will lose a lot of bookings by asking for a 9:00 am check-out, speaking from my own observation of the typical Airbnb guest.
If you do go down this road, I hope you are in my area and let me know, because I will send all the guests who pester me for an early check-in your way.
We tend to get people who want to check in early, arrive later than they think they will and then leave at the last possible minute.
Personally, I think you’d be limiting yourself.
There is no way on this planet that I would book a rental with a 9:00 a.m. check-out. Never going to happen. We offer a noon check-out partly because it suits us and partly because I’ve noticed most Airbnb guests are in their 20’s and 30’s and have zero interest in getting in and out early.
About twice a month we get retired or semi-retired people from the suburbs of Boston who are coming to attend an event, or people traveling for the first time with small children who need and want to check in early. We do all we can to discourage them from booking with us - our listings are not right for their needs.
If yours is - there might be a whole untapped market there and you would have it mostly to yourself.
That’s the earliest check-out time I’ve ever heard of.
The other thing is - when people want to check in early, I see it as a red flag. Why are they so concerned with getting to their lodgings early? We’re not a destination Airbnb, I do not expect people to come to our listings in order to hang out at our house. We’re a place for them to sleep, shower, eat, and relax a bit after their activities. I am always slightly suspicious of people who want to be in the house for the afternoon. That’s not what traveling is for.
Anyway, that’s my two cents.