Tom, Thank you for explaining that.
Input : 100-240v~50/60Hz 0.6A max
Output: 9V - 1A
This is what is written on the Adapter. The Servo is for feeding the fishes. It will be working once a day for a minute max.
The Max load on the arduino will be from the 2 Relays as one is for light, which will be on for 12 hours and other is for Pump, which will be on for 16 to 18 hours.
I was planning to use a 5V - 550mA mobile charger to power the Sensor Shield board externally. Will that work? Or should I continue with the 9V adapter.? (PS - I have 12V-1A adapter too.)