Personally, I think the 10wt might be your best option now, but others may not agree. Its big for most trout and redfish, but if 20-30lbers are in the area it wouldn't be too much for them. And it gives you more versatility I think. Fight the wind even more than the 8/9 and you can go after bigger fish like tarpon with more comfort if you travel. My dad, brother and I took a trip with a guide in the Siesta Keys area of Florida and he had provided a 10wt outfit and all we were catching were mackeral, ladyfish, and the occasional trout. They might have been a little more fun on a lighter rod but I still had fun with it. Since space in the rod tube is limited (3 guys sharing one tube) the only flyrod I bring with me to Florida now is a 4pc 10wt (was a Cabelas but I broke that last year and haven't got it fixed yet so now its a Redington). As long as you can handle casting the bigger rod all day it shouldn't hurt you. I guess it really depends on your chances of catching bigger fish. If fish over 10lbs are very rare then you'll be in for the occasional scary moment with the 8, but if big fish are a once a trip type thing or more common and the winds are blowing more often than not I'd rather be a little overgunned for the little fish to handle the big ones.

That said, I am now considering picking up an 8wt to have an option in between the 6 and 10 but if I were sticking with one rod I'd stay with the 10. I just feel more comfortable knowing I've got a little more if I need it.