Funny, my Ariat boots are the only ones I don't have this problem with. I wear an 8 for everything, but with boots I sometimes have to go to a 8 1/2 and then they are just slightly too big. I have tried insoles, but they have not worked very well for me. Since the foot is lifted up a bit, too, the pressure on top is uncomfortable. And it doesn't help that most boots are made in China. You may want to try the HH brand - I know a lot of folks who swear by them.
The harder you fall, the higher you bounce.