I have no specific setting on android or n9 to get BlueVPN working. Not even commenting out the DisablePlugins in N9, no settings on BlueVPN. I don't have Nexus. I can get it working from ICS, but not from JB. In JB there is some unobscure error, maybe my ROM is not compatible with BlueVPN.

From JB I'm using Android built in BT PAN connection (to n900...not N9). Others have tweaked BT PAN working on N9 also.