I for one took this statement to mean that Romulans literally live on the surface of stars
Careful! "Balance of Terror" is an analogy to the WWII scenario of an Anglosaxon destroyer hunting a (Japanese or German) submarine.
In the latter case, the Romulan Commander was eager to see the planets
of home, because "star" in old German can equally mean "planet".
Good Point! As a matter of fact the older Romulan makes a remark according to which him and the commander have seen "a hundred campaigns together". While not solid evidence (what kind of campaigns and against whom?)
I think it does qualify to support your theory.