I'm not sure if it's powerful enough because you want to use a servo. Servo's are power hungry!
And for supply voltages the current rating works the other way around. Aka, the supply need to be able to deliver what the load asks. So a voltage source with a higher current rating is just fine. Also, the 1A for Vin is not the rating what it draws, but what it maximally can deliver on the 5V line. But it's heavily overspeced. Yes the max rating of the regulator is 1A but that is with sufficient cooling. On an Arduino it has not. With 12V on Vin you can barely connect one or two leds.