We have been the first stop several times at Pop, but last December we stopped at Caribbean Beach and AOA first - so about 50 minutes if you stop at other resorts. I have waited as long as 20 minutes waiting for the bus to fill (late at night). It takes us about 10 minutes to get to the bus from the gate.
Best case - 10 minutes to get off the plane, you walk 10 minutes, the bus is boarding and ready to leave, and you are the first stop. 8:10 arrival at Pop
Worst case - 10 minutes to get off the plane, 10 minutes to walk to bus, bus is waits 15 minutes to fill up, you stop at 2 other resorts and the ride is 50 minutes. 8:40 arrival at Pop.