1) I think the 9" single six will be a bit unwieldy. I had one in 6" and I think that was an excellent, well balanced barrel length for that gun. I sold the gun because my hands are bigger than the gun was designed for and I could never master it in field positions because of the awkwardness of the grip.
2) I've shot both the Ruger and the Buckmark, and have seen both perform in bullseye competition. I cannot for the life of me understand why anyone would buy and keep the Ruger. It really is dramatically inferior to the Buckmark. I attribute the continued good sales of the Ruger purely to advertising and to the satisfaction of low expectations among their customers. I've seen people get rid of their Smith and Wesson 41 target pistols and switch to Buckmarks and call them superior to the 41. I've seen too many of the Rugers literally fall apart on the shooting line-- and what triggers! They're terrible, and a trigger job doesn't seem to help much unless you go with something like the Volquartsen treatment, after which you have an awfully expensive Ruger that's difficult to sell, costs as much as a high-end target pistol, but isn't as good.