Union Forces…

Hey all, So i got this board :lib Tech TRS C2BTX 2011 (157 long and 25.3 wide ) and these bindings : L/XL Union Force (link – Force | Union Binding Company ) The problem is that the salesman told me to go L/XL with the K2 Darko boots (US 9.5) that I also bought but when I place the boot in the binding there is just a little play. Is this normal