For future reference, gordie, the way odds are expressed is that the first figure is the amount you win if you wager the second figure. Therefore, put £9 on @ 4/9 and receive £13 - the £4 you win plus your initial £9 stake.
Have you ever seen a poor bookie - they know the lay of the land - the last time I looked it was 4/11 for 'No' (that's odds-on and shortening) and 13/5 (that's odds against and drifting) - looks pretty cut and dried for the 'No' vote!