Fromeurope, yes you can wait to make a PS once you arrive at the AKL resort. There will be a "WDW dining" key on the phone in your room at AKL, and you can just press that to reach a Cast Member to make your PS. This is an option for you for any PS at any WDW restaurant. Granted, the closer you attempt to make a PS to the time you actually want to eat there, the greater your chances are that you may not be able to get one for the time you want. Since you are staying at AKL, trying to walk-up without a PS may not be inconvenient for you...if the wait is long you could always try another time or night.