how to get child account to be able to access online features in NBA2k17

The thing is this there are certain features that are blocked by EA for child accounts.

Here is an EA support article explaining this.

EA access for child accounts

Hello PhilipBasgal,

Thank you for posting on the Xbox forums. We understand that you are interested in changing a child account to an adult account. Once an account has been established as a child account, it cannot be changed to an adult account until the child turns
18. The best way to manage the child account is to
add it to a family. This requires an adult account to add the child account to the family. Once the child account has been added to the adult account's family, the child account will be able to access online features. Be sure to let us know the results!

Adults have access to parental monitoring to limit the accessible content on their linked child's account, this limits the access to content that isn't in there age group and certain online features

Also, if there are no gold accounts on either Xbox, they may not be able to play online. If there's one gold account and one of the xbox ones is set as a home console, there is a way to share gold on two consoles at once.

First, log out of the gold account on the home console, and allow child account number one to log in there. That account will be able to log into and access online multiplayer so that the kids can play together due to the shared gold feature of a home console.
Then, on the second xbox one, log into both the gold account and the second child account. Then use the second child account to log into the game. You should be able to use gold in that way on that console as long as the gold account is logged in.

Adults have access to parental monitoring to limit the accessible content on their linked child's account, this limits the access to content that isn't in there age group and certain online features

But I'm an adult and I don't have parental monitoring