So the most user friendly way to do this would be to download the Virgin Media Connect app, connect it to your hub and then manage wifi devices.
I'll apologize in advance that I'm not that advanced a user with the Connect app, but I know you can turn of devices using it, I'm not sure if they can be configured with daily times or not.
Devices can also be managed from within the hub web login too.
Let us know how you get on.