You did it! Well, someone did it, at least.
You may recall about a year and a half ago, Microsoft began the process of making Xbox 360 games playable on the Xbox One through backwards compatibility, and they put out a call for which games Xbox owners would like to be made available through this service. Naturally, Mega Man 9 and Mega Man 10 were perfect candidates for it.
Fast-forward to today, and the time has finally come! If you've got either game on your Xbox 360, then you can redownload it on your Xbox One at no additional charge. If you've got Xbox Live Gold, you can also take advantage of the cloud saving feature to move your progress over as well!
Hm, maybe now I can stream these games on the Nyteworks Stream sometime, whenever I get around to bringing that back. Unfortunately, I don't have either one on Xbox 360 -- I went with the Wii version, as I favored that controller's Dpad, something which has not been an issue for me with Xbox One.
That just leaves the question of whether or not the games are streamable with the Twitch app on the console. Not every game is, as my wife and I have found out through previous attempts with Castlevania: Symphony of the Night and Mighty No. 9. So if anyone is kindly able to verify that they can be streamed with the Xbox One Twitch app, then I can purchase with confidence.
Oh, and in case anyone is interested, Beat'n Groovy from Konami is also backwards compatible now, too.