and ...
pls read what @MarkT said:
You need more than 5V and you must not power it via the Arduino board!
You need at least 12V from an external power supply for the motor shield.
The amps are determined by the connected motor.
So - if the motor datasheet tells you, its max. current will be something like 1A - your power supply has to deliver at least 1A (normally I add 10-20% extra, when I buy a suitable power supply).
A 9V battery won't be able to give you the required power, maybe just for a very limited period of time.