Can be done manually, if a bit tedious. Grab a transparent circle image from the WEB. In this example, a black circle was made white by adding the Negative effect.
Overlay the image on a higher track than the background. Use the Motion effect to scale it, then manually animate the motion, adding as few keyframes as necessary.
http://help.nchsoftware.com/help/en/videopad/win/effects_animating.html
If you make a mistake immediately press <ctrl-Z> to backtrack, step-by-step.
Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the chevron to the right of the Save Project button on the toolbar.
Motion_track.mp4