LumaFusion is great. Impressive speed, even on an older iPad. I honestly didn’t think it was possible. You guys are doing great stuff. And thanks for letting me own the software, not just rent it.
Yes. You can explicitly set your project's aspect ratio, including 9:16 (which is the iPhone vertical ratio) and edit it that way. You can also include vertical video in a non-vertical project with black bars on the sides ("fit"), by cropping ("fill"), or stretching ("stretch").