Obviously you'll need an app that supports 3D playback such as Kodi.
If you ordinarily have your U9-H configured with a 4K display to use a resolution of 4K2K @60 Hz you'll first need to adjust that to 1080p @60 Hz in the display settings on the U9-H.
Playback your 3D source material as you would anything else. (Some 3D capable TV's may also require manually setting to a 3D mode as well. For example, I have to specify if the source media is side by side or over/under & choose the respective setting on my TV to match.)
That's it, simples . (Don't forget to revert your U9-H back to the 4K2K @60 Hz resolution after you've finished viewing your 3D media if you then want to view something else in 4K again.)