Screen Ratio during Chromecast

[Saviorself]

I'm hoping some of the more craft members of the android community can help me out. I'm planning on using my Nexus 9+Chromecast for some upcoming PowerPoint presentations I am doing for grad school. Our projector rig has an HDMI input and I've tested to ensure compatibility with Chromecast, which has not been an issue so far.

I know that the Nexus 9 has native 4:3 display ratio, but I'm curious if there is a way or an app that can allow me to bypass this so that I can force a 16:9 display ratio. Certain apps do not have native Chromecast functions, PowerPoint being one of them, and when they're displayed on widescreen TVs or projectors the picture comes out with subpar resolution and the ugly ol' black letterbox bars.

What solutions or work-arounds are there for this issue? At the moment this is something I need for presentations, but in the future it would be nice to play KOTOR or other Android games using my Chromecast and I would prefer the display to fit properly.

I'm open to rooting my device if its necessary but I'd prefer not to if possible given the higher level of complications and risk of failure Android 5.xx presents in the rooting process.

I appreciate any and all feedback!