My kids bypassing Netgear Controls (Armour and Circle) by creating new devices?

Kids a sneaky. 

And they're great at googling for ways around blocks/settings. 

whether that be by adding new devices or spoofing mac addresses. 

Or even plugging directly into a satellite or the router with their own device. 

They'll do their best to find a way around. 

Have you tried using the guest network option? 

Setup the primary with your devices and set the ssid/password and don't give the kids access to that. 

Then setup the guest network and give them the info. then you can turn it on/off at will. 

Or use access control to block new devices. So if they do add a new device, it automatically gets blocked.