Currently Adobe Clip is not capable of adjusting the speed of video recorded at higher frame-rates ("slow motion" in e.g. iOS). The slider for controlling the speed of a video is disabled for slow motion videos, as described in this forum thread (link).
Fully adopting Adobe Clip as my main video editing tool would require a separate app only to adjust the frame rate. I used several apps for video editing, including paid ones, and adjusting video speed is present in e.g GoPro Splice, GoPro Quik and Pinnacle Studio Pro. These apps have different methods of treating slow-motion/high frame-rate videos, whereas Clip currently offers no feature (speed slider is disabled, as mentioned by @frankielouise).
Someone commented in another post that you should only shoot with higher frame rate what you will actually use it as slow-motion. While I don't shoot everything in slow-motion, I believe the whole point of using a mobile phone to make videos is to have flexibility. As they say, you can always speed-up a video with higher frame rates, but you cannot slow down without compromising quality. Of course, you need tools for that It would be nice to have Adobe Clip support such feature.
In relation to using frame rates higher than 30 fps, I imported video from my Kodak sports camera shot at 720p60. Adobe Clip ingested it and correctly scrubbed it, but failed to render it properly: I get some frames at the beginning of the rendered video, and the rest of the video is blacked out.
Please, fix correct rate conversion from source rate (60fps in my case) to rendering rate (say, 30fps). I did not need slow-mo, so all that is needed is just throwing out every other frame.