More info is needed.
Are you taking Magical Express from the airport or renting a car? If you are renting a car, and there is no flight delay, you will make it without question. If you are taking Magical Express, chances are that you will arrive in time. Worst case scenario would have you arriving at Jambo House at about 12:30.
Is Magical Express delivering your checked luggage or do you need to pick it up yourself? Picking it up yourself will add to the amount of time you would need to get out of the airport.
Are you on a dining plan and do you plan to use it to pay for lunch? If the answer is "no" you can hit Sanaa as soon as you arrive at the Lodge (have Bell Services store the luggage you have with you, then walk over to Kidani or catch a bus - I think you need to take the Downtown Disney bus to get to Kidani from Jambo). Then you can check in after lunch.
If you do need to check in first, you will have to add time to do that.
The good news is that Sanaa is generally not terribly busy at lunch, so even if you miss your ADR time you can probably get in.