how to use scene/alphaover on top of video clip?

I’ve gone over the forum until I hit the patience threshold and no solution yet.
My goal is to just stabilize a video using tracking and overlay some (scene-generated) text credits. I thought it would be easy to assume the scene would default to an alpha=0 for the background.

Here’s my desired steps:
Layer a scene using alphaover on top of a video layer in the VSE. That simple. Does it work? I’ve tried toggling the OpenGL preview in the VSE, no luck.
I’ve tried making a world-background with alpha = zero, no luck.
I’ve tried a backdrop plane with an alpha=zero material, no luck.

If I use the compositor then basically the VSE approach is unnecessary. But my footage is upside down and the flip checkboxes in the VSE are convenient.

If the scene you’re overlaying in the VSE has alpha data then it will show in the image preview but ONLY if the blending mode is set to alpha over. If not, well then transparency data are ignored and the top strip obscures whatever is below it.

If you want to stabilize your footage head straight to be movie clip editor, load the clip there, and track two points for stabilizing location and rotation. You don’t have to turn to the VSE for tracking. Once you’ve got the clip stabilized, then render it out and load the result (be it an image sequence or a video file) into the VSE.

Adding titles from another 3D scene should be straightforward using alpha over.