Is it possible to clear the debug stream during debugging?
RobotC only gives 2 statments in its documentation:
writeDebugStream(); and
writeDebugStreamLine();

is there something else that allows for the stream/window to be cleared/refreshed?

I haven't tried this for RobotC, but when you're writing console programs, you can use the '\b' escape character to delete the previous character. It is how Tetris can be done on cmd.exe
Again, I don't know if this works on RobotC, and I don't have it installed on this machine.