Virtual terminal not showing data
Try calculating the baud rate for it to be about 4800 on the simulation, even if in reality you'll be transmitting at 9600. Proteus rarely runs at 100% real time during simulation execution and data sync can't be achieved between the simulated devices. This has worked for me before, hope it does for you. 

Another thing you might want to double check is that the TX pin from the master goes into the slave's RX pin and vice versa. It's a common connection mix up.