No, Windows will not recongnise the RS232 device. The VAGCOM software will try to use the comm port resource when it is loaded and/or when it attempts comms through the com port. If other software is using the com port at that time e.g. TeraTerm, then VAGCOM will not be able use the com port.
So long as there's no other software trying to use the com port you've allocated with whichever RS232 D9 connector you're using then there should be no problem
