I have a lot of entry in the same location. I would like only to get the 10 latest added items using Geofire. I know that it can be done easily with firebase using Query.lim
There is no way to limit the number of keys from Geofire: it will return all keys that fall into the range you query for.
The only thing I can think of is to not insert items if there is already another item in its vicinity. You're essentially clustering items while writing to the database in that case.