I'm confused about whether you want a 9" unfinished block, which gives you an 8.5" sewn/pieced block, or a 9.5 inch unfinished block that gives you a 9" sewn/pieced block.
I only bring this up because I've measured twice with the wrong measurement (used the finished size of the block to cut, not the unsewn size) and therefore cut wrong...a painful, expensive mistake!
The advice you've been given by others is good. Now you just have to figure out which method will work for you.
One hint - if you're cutting folded fabric, press the folds with your iron. Can't remember where I learned that trick, but it seems to minimize 'elbows' made when cutting through the fold.
Good luck on your quilt!