This is an old topic but... I just developed a Delta 3200 in DDX 1+9 using Andrew Sanderson's recipe and the result was amazing to me. 20C, 45min, continuous agitation in the 1st min then stand. Great tones, lots of details in the shadow areas. After using this film forsome years, I think this is the optimal way of developing it.
I also developed a Delta 400 in DD-X 1+9. I found no reliable recipe so I created one: 20C 16min stand. I also developed a Delta 400 by the book to have comparison. I put the two negs on a lightboard and could not tell the difference. (Same camera, same lens, same place, same time.) This recipe is not a push, it's just right on box speed.