2 routers (1 for adults, 1 for the kids)

1 account 1 gateway per address 

You order internet from a different ISP with the most likely being your local cable company followed by FWA from T-Mobile or Verizon.

This provides a redundant system in case ATT Fiber OR your kids ISP have a problem you should still have one working provider can share until service is restored from the down provider.

You said you want independent routers, but you didn't say what you intended to gain by doing so.  If you could explain what benefit you want, perhaps we can guide you towards a solution for that without a second Internet provider.

... you want better Wi-Fi coverage for each?

... more bandwidth for both?

... different security settings?

*** The Reason: ***

I would like 2 independent routers, 1 for kids and the other for the adults. I have 3 boys, ages12,13 and 15, with a dedicated router for the kids I can manage their internet time by interrupting or removing the power supply.

I can manage [the kid's] internet time by interrupting or removing the power supply.

That was the question I was looking for.  This is the need, two routers was your solution (which may or may not be the best solution).  The original responders assumed that you wanted two different service gateways.

Keep in mind that the BGWxxx series of Gateways has the ability to be controlled by Smart Home Manager and let you create profiles of devices that can be manually disabled or disabled via time-of-day restrictions.  This may be one answer.

Another would be to get a Wireless Access Point, connect it to the Gateway and give it a different SSID and passphrase, and don't share the SSID/passphrases on the Gateway.  Thus you can turn off just the Access Point and disable them.  

You can also get a Wireless Router and put it behind the Gateway... that would give you two routers, and you can do the above.

You can get two Routers and place them both behind the Gateway, but one of them will be subject to double NAT unless you also get a block of Public Static addresses and configure at least one of the two routers with a Public Static.

Ideas are abound! 

Thanks .

Our routers have option to turned on Guest Network, that can be used for any purpose buy any one, You can set it up thru SHM set separate name and password for it. Also can be used as dedicated 2.4 Ghz network for any smart devices requiring a 2.4 Ghz. 10 Clients can connect to it by default but that can be increase.