just do like the others have said, snake bags, foam box to keep heat in and cold out and the box up on the seat, you will be fine. i would put a thermometer with a probe in it so you can check temps while your driving and know whats going on inside.
i drove 3 snakes from el paso to MA back in september and it went fine. 9 hours wont be too bad. just get them into their tubs with stable temps as soon as you get to ur destination and let them chill out for a few days. good luck