A lot of fly fishermen are moving towards longer rods. My go to streamer outfit is a 10ft rod. I wouldn't go under 9ft for that unless you have a specific reason to.
For the reel, you will want to get one in the same wt range as your rod in most cases. That will get your rod balance in the ballpark and ensure you have enough space in the reel to fit your fly line. Then use fly rod balancers to get the rod and reel perfectly balanced.
With streamers good rod/reel balance helps you have much better control of your rod so you can make great presentations.