When on ~1.8, I was able to login to Minecraft Realms through Xbox One. I had set my privacy settings correctly. After downloading the 1.9 update, I am no longer able to login, with no changes to privacy settings. The specific message is:

"You cannot play online multiplayer through Xbox Live because of how you account is setup. This can be changed in your privacy and online safety settings on Xbox.com."

I have verified the privacy settings are the same as they were, and even tried toggling them to the defaults for an adult account. Nothing seems to work. I can successfully login on other platforms (iOS, Nintendo Switch).