I have Deco M9+ at home with Netgear wifi extender EX2700.  In parent control, I set no internet on my son's devices at 10 pm everyday.  However,  he still can connect to internet.  I asked him how, he said when internet disconnected on his devices, he switches his connection to wifi extender.  I thought M9+ controls over the extender when it connects to M9+.

The wifi extender in the garage for my security cameras and sprinkler system.  I am guessing that I can add the extender into his devices's list but I don't want to.  Is there another way?

Thanks