Hi everyone! I'm completely new here and to quilting so please bear with me!

I've just joined an international quilting group and the first project of the year is an oversized 9 patch. I need to make a 23" square 9 patch block. I understand that it is to be made of 9 smaller 8" blocks, and I just want to figure out how much fabric I need. I have no suitable scraps since I'm so new! I think I could just choose nine colours, but I'm wondering how much of each to get. I know I need a 1/4" seam allowance all the way around. Should I just have the fabric cut into fat quarters and work from there? Any ideas are greatly appreciated!
Jamie