Yes, you can test 2 operators at the same time using TEMS Investigation 9.0.0. You need to connect two phones. Also, you may need to connect two dongles if you are using phones from different versions of TEMS Investigation. You need only one GPS, not two.
The logfile recorded will be only one, but you can generate the report based on MS ( ie, MS1 or MS2).
The error “LICENCE CHECK FAILED occurs when TEMS cannot detect the dongle. Are you using the same phone model? Does this error occur for both phones? Please answer these questions, so that I can see how to help you out.