The Verge is engaging in a little piracy-fuelled journalism, reporting the discovery of an Xbox app in a leaked build of Windows 10, also noting Cortana is integrated into the upcoming operating system that was never known as Windows 9. However, it sounds like while this will offer access to Xbox dashboard functions, it will not include the ability to play games:

Elsewhere there’s also a new Xbox app. It appears to act as a gateway to the entire Xbox ecosystem, including access to achievements, friends lists, activity feeds, and the Store. Microsoft notes that it’s an early preview of the app, so it may well include SmartGlass integration in future. It’s also a first glimpse at how the software maker is designing its native Windows 10 apps, and the calculator app has been updated in a similar way.