You only wanted
to crop it.

Trim, crop and cut dead time from a video. Nothing else to learn.

Download

Free and open source. For

$ du -sh /Applications/*
Premiere Pro8 GB
DaVinci Resolve3.7 GB
Chyk73 MB
$
Approximate install sizes on macOS.
Chyk cropping a video to 9:16, with the trim box on the filmstrip below

Does one job well

Download

macOS

Apple silicon .dmg Intel .dmg

First launch: if macOS says the app can't be checked, open System Settings → Privacy & Security and click Open Anyway.

Windows

x64 .exe

One file, nothing to install. If SmartScreen stops it, click More info → Run anyway.

All releases and changelogs