The amount of time it takes to get from your plane to a ride is a bit variable. Any of these = an unknown:
1. flight delay
2. time to collect gate-checked stroller?
3. time to get from gate to main terminal via airport monorail
4. time to pick up luggage, get food, or shop- while all of these are optional, they are all options you could easily opt to do.
5. find ME +wait time to board ME bus.
6. wait time for ME bus to depart.
7. drive time from MCO to WDW.
8. Is your resort the 1st stop or last stop that ME bus makes?
9. Online check-in? or wait in line to check-in?
10. Line to drop off luggage? What If room is ready? maybe drop bags in room?
11. again- optional- but whenever we drop bags off in the room, well, it just takes a few extra minutes. Everyone unpacks SOMEthing.
12. From 1/2hours pre-flight take off to luggage drop...is likely 4+ hours. Someone in your group will be hungry.
13. I don't know your family, but making any flight that lands at 9:35am = getting up very early, and likely getting little sleep = tired.
14. Time waiting for transportation to parks
15 security entering the park
16. all ticket media and everything goes smoothly?
16. time to get from park entrance to actual ride.
Now I know someone who once made if from landing -no checked luggage, no stroller, in the days BEOFRE added park security, and EVERYTHING went PERFECTLY - to the GATE of MK one hour after landing!
I have also experienced flight delays (alone) of 2+ hours. If your flight is 1st flight out of your home airport=highest odds of on time.
More typically, if you go directly to the bus, no delays, no long lines.... allowing about two hours is probably a reasonable allowance.
So noon is likely a reasonable time to schedule your 1st FP, but just mentally allow that you might not make it by 1pm. You can always modify/cancel/re-book a FP. If possible, Id schedule your least important FP an noon, then your 2nd choice FP starting at 1pm, and the FP you most care about as your 3rd FP (starting around 2pm?).
With little kids, I likely wouldn't hype (tell them about?) any FP scheduled for that day, so nobody's crying if you don't get on 7D that day. Even with adults, we treat arrival day FP's as a surprise bonus if we happen to arrive as planned, not an expectation.