If you turn the router off at the electrical socket it will not transmit anything.
If you use the access controls it will still be transmitting wireless signals. It will only stop the devices that you have set to be blocked from accessing the router.
If you need it turned off you could use an electrical timer plugged into the electrical socket and set it to turn off and on at your desired times.
I am presuming that you wish to block access to a child between those times. If that is the case obviously turning it off and on could be easily over ridden.
Access controls can also be over ridden and it is not hard for any computer literate child to find out how.
As per my first sentence in my previous post:-
"If you turn the router off at the electrical socket it will not transmit anything".