I've found the one on 10 to be fairly busy in the past as well, but the one on 9 was always empty except for me. 9 forward has lots of machines and is really tucked away. I'd recommend being aware of where they all are, whether you'd rather go vertical or horizontal to get there (I'd rather go down an extra floor or two than walk most of the length of the ship), and then be willing to leave one place and go to another if need be, particularly if you need more than one machine.