"The Lost World" is an example of where "world" has a meaning other than "planet."
The ST2 script specifically says "planet". I'm not aware that "planet" has a meaning other than "Big round thing that orbits a star."
"Instead of a dead moon a living, breathing planet."
In the movie itself (in the presentation video) Calor Marcus' "planet" is born out of a "moon".
It would seem that their terminology is all over the place.
Considering how fast Genesis forms, it is a far more logical and easier explanation that the Genesis-wave re-formed Regula.
It has an "instantaneous affect" on an already existing body; but I think it would take a little longer than just a few minutes for all that mass, all that matter to gather to form a planet - Genesis effect or not.