Shut off network for a device at a specific time using Mac address? RT-AC88U

I have an Asus RT-AC88U router and was wondering if I could set it to shut of the network for a device using it's mac address at a specific time.

In short I want my sons tablet to be shut off the network at 9pm each night and then back on at 6am so he doesn;t wake up and try and get on his tablet during the night.

I've poked around at a few settings but could not find something that did this, maybe I missed it.

Thanks for any help