Unfortunately, Macs don't work like Windows machines, the drivers are part of the operating system and can't be updated separately, in essence there is no driver version to check. And I am on the most current version of MacOS, so there's nowhere to go until they put out another update; I doubt that will change anything. If anyone knows how to get around this Mac issue I'd certainly be open to it, but I've never heard that such things are possible.
I don't know anything about DirectX vs OpenGL unfortunately; it's just amazing how much differently the two games run. Wurm Online looks like such a great game, I really wish I could get it working!