Short answers: there is no "best" when it comes to kayak designs. A creek boat (any of them) will not be too long for the runs you mentioned. Creeking in a playboat is a good way to learn why people creek in creekboats, which is to say playboats make creeks harder while creekboats are designed to make creeks easier (notice I said designed). At your size, go with the larger boat in a given design series (i.e. Nomad 8.5, Super Hero, Mega Rocker, L Burn, etc.). Personally, I have been loving my Jackson Super Hero (7'11'', 87 gallons) for every kind of hard whitewater that I have encountered this season (class V on 20,000 to 100 cfs, clean to manky, big water to waterfalls). I find it to be much more user friendly, comfortable, and ready for overnighters than the M Burn I used to paddle without sacrificing the improved handling and playfulness that a planing hull offers.
FYI, I'm 5'6'', 150 #'s, size 9's, and I paddle for Jackson's Regional Team. So, add as much salt as you like to my recommendation of the Super Hero.
To summarize, you should base your boat buying decisions on how the boat feels to you (Demo!) and how it works on the type of water you want to paddle. You should not base your decision solely on a boat's stats (which are often incorrect), what other people are paddling, or what someone on Mountain Buzz tells you.