I have done a D9P with just two different fabrics, and with totally different for a 'scrappy' look, it is important to have dark fabrics on the outside corners and centre, and light in the four central outer blocks.
If you want a symetrical look when you cut through the centre, just swap over the top right for the bottom left on every block and resew, or if you want a totally random look just turn each corner any which way you please.....
Hope this helps.. Here's a picture of the charm squares quilt and two colour version :D