It sounds to me like the pattern would then want you to cut those squares in half on the diagonal and maybe even into fourths. You can still easily do the 9" block and use your scraps. Just measure what size a completed triangle is and see if that is small enough for your scraps! Cut it out in paper and use the paper as a template for the scraps where the piece isn't quite big enough for the square but ample size for the triangle acheived in the second cut.