Look up the batteries....
http://data.energizer.com/
has good info.
Usually, breakers and fuses are used to protect wires. If there is a short circuit or overload, the breaker/fuse will pop before the wire gets hot enough to cause trouble (trouble usually = fire).
There are self resetting thermal circuit breakers available at auto parts stores. Or you could use fuses, from an electronics store (even Radio Shack has them) or automotive store.
For a 10 amp circuit, if you use 18 gage wire and 10 or 15 amp fuse/breaker, everything should be fine.
An you could use a normal switch to turn power on and off.
Also, be careful with battery wiring...from the users manual:
"5.4 Reverse-battery
The motor driver boards do not have any protection against reverse-battery. If user connects the battery or power source wrongly it will damage the on board clamping diode and further burn the driver. Thus please be careful during making connection. "