why 9 pin on VGA (15 pin HD) plugged?

older consoles have the 9 pin on the vga video port plugged.

most newer monitors have a monitor cable with all 15 pins including the 9 pin. therefore cannot connect to them.

according to vga 15pin hd pinout specs, the 9 pin is not used.

are there adapters available? or an extreme measure, just break off 9 pin?

thx