Well that's an interesting question. As far as I know, SureAI hasn't put that much thought into geology. As a geologist, the whole story of a large meteorite crashing onto Vyn and splitting the supercontinent into the continents we have now is nonsense of course. Actually, it's more like an ingame myth anyway. If we take a geologic approach and assume Vyn is round, because it has a day-night cycle and different climate zones due to the smaller angles sun rays are hitting the planet at higher latitudes, we have indications for a round planet. Furthermore, there are seasons in Vyn, or I guess at least there are because most people don't consider a world without creating seasons. To get seasons on a real planet, you have to have an inclination in the planets rotary axis, which is about 23.5° on planet Earth. This inclinination is highly important for the zonation of climate zones unconsciously applied to most fantasy worlds. As a Beta tester I can tell you that climate zonation has also been applied to Enderal (at least sort of) as well, it's more like NW (cold) - SE (hot), similar to Nehrim. Under the assumption of cold and warm water ocean currents playing a vital role in the thermal circulation of Vyn, that would even make sense. This is the reason, why have palms in Ireland while on the same latitude in Canada you can find polar bears.
You might take a look at this unofficial map created by one of the users in the German forum, which shows the position of the continents in Enderal based on Vyn to get a better idea of the relative positioning of the continents:
http://sureai.net/forum/download/file.p ... &mode=view
So yeah, just looking at some details I come to the conclusion Vyn is indeed a planet, if we assume it's working with similar processes like Earth. But in the end this is still a fantasy game and nothing of what I said must apply to that world.