I don't know about a Vera2, however, a Vera3, in theory, because it has WiFi capability, could work. (If by tethering you mean WiFi between phone and Vera.)
Having said that, I think that a better option than phone tethering might be a device (hotspot) with an Ethernet port that T-Mobile would provide with the $20/month plan - though the device might cost a few bucks.
Wired connectivity for Vera is a lot better than WiFi. I had to write a little program to ping my Vera every minute to keep alive the WiFi connection - and still flakiness.