Well, now, you don't say which airline you're using but... if it's a participating airline, you can check in for your flight AND check your luggage through to your home airport as early as 5 AM that day (but not later than 9:05, and yes I added a thirty minute buffer in case the RAC is busy

)
Then use Disney transportation to get to the Grand Floridian (bus and monorail), eat, look around, then head directly for the airport via either prearranged livery service, or take a cab.
If you're not flying on a participating airline, you can still do this - you'd need to take a taxi WITH your luggage to the GF, since luggage isn't permitted on the buses (please, no "But I saw a family with a hundred and eighty three suitcases on the bus to..." arguments - Disney's policy prohibits it

), then another cab or a town car to the airport.
I keep referring to the Grand Floridian even though your breakfast is planned for 'Ohana. If you'll be carting your own luggage, unless you have a reservation for the instant the restaurant opens - 7:30? - or at least the first fifteen minutes, or right at 8 if that's opening time, you're really not going to have enough time to eat, get to the GF (would involve yet another cab) then get to the airport with a comfortable cushion.