Yes 8' foot oars are fine for the BBoat. I used 8-1/2" footers and they work fine too. 9' foot is too long. I sold my last Buffalo Boat a few years ago and wish I had it back at times. Although I'm beginning to think my little 9' foot one man boat is one of the best things I ever made. I have the frames and dimensions for that boat. I doubt I'll ever make it again because I have one and I'll never sell it. But I should take a deep breath and find the time to make downloadable plans for it.
I told my wife I was only going to build one more boat. From there on out it will be maintenance only on what I already have. It's going to take a while. Once you retire and get a taste of lazy it gets addicting. Too cold for fiberglass in Winter. And fishing season when it's not. It will probably be a year and half from now before that last boat is done.