Lots of people have mentioned this before. If you have ample amounts of time to study during the 9 days (not just 1 or 2 hours), you should try destroyer. I haven't took my DAT yet, but people say it helps with the conceptual questions for organic and GC. From what I heard, Cliffs Bio is the best way to go for biology.
Are you scoring 15 in all three sciences, or decent in two and really low in one? That might help you concentrate your study efforts. Good Luck