Xbox One version is not 900p it is a scaling resolution
this is directly from Michael Condrey and Glen Schofield
Minimum Xbox One resolution is 1360×1080, and dynamically scales from there to full 1080p. That’s over 50% increase from last year accoeding to Condrey. The game runs in native 1080p on PS4. Both versions run at rock solid 60 frames per second.