There is already a question about Sleeping at Frankfurt Airport. We are in the same situation with a 9 hours stop over during the day after a redeye flight, except that we would like more comfort than sleeping in the airport lounges since we will be travelling with a small child.
Are there hotels within the airport or close to the airport which offer day-rooms? Something that can be used from very early morning to early afternoon. This is something I've seen in Asian airports but never elsewhere so far.