You can do your quilt any way you want. The D9P I made had the same fabrics in the corners of the 9 patch, the same lighter colors in the 4 side patches, a different dark color in the center of the 9 patch. To get the effect of the D9P, I think you need to at least have the fairly standard dark colors in the corners and center, and lighter colors in the other 4 squares (or the reverse). But each square could be different fabric if you want.
I think the same would be true of the D4P - to have dark colors in the opposite 2 corners and lighter fabrics in the other opposite 2 colors.