One of the easy ways to make a two color 9 patch is this:
Cut three strips of two different fabrics, all the same width. My suggestion is to use 2 1/2" width, cut from 2 fat quarters, Fabric A and Fabric B. Sew 2 sets of fabric A + B. Make as accurate 1/4" seam as you can. Use the remaining strips to create the following sets: A+B+A and B+A+B. If you have been accurate in your stitching, the width of your sets will be 6 1/2 inches. Cross cut your sets into 2.5 inches and arrange the pieces, match the seams, sew and you're done.