A passport is all the ID you need, and you can top up online, at 7-11, at ATM's or through the phone app. You only need to work out what you want the SIM for, i.e., phone calls or data (or both) and buy an appropriate package, if you buy from the airport vendors there is some chance they may be able to sort you out with a reasonable package, buying in 7-11 you won't get that assistance.