If the device is automatically set up to do so then yes. I reset my router (effectively what the timer switch would do) every now and again (used to be daily) and whenever I turned it back on my phone / computer would auto connect back.
As the password / SSID are stored device side they will auto connect whenever they detect the network again.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.
There's nothing really for me to add to this as @Shafreya has covered this for you but just to confirm, if your devices auto connect as they do if you reboot there should be no reason why they would not do this if you have the hub on a timer.
Just monitor the experience over a few days if you try this to see if it impacts your streaming in a more positive way and if so then awesome!