idk are you planning on using the wholes pace to grow? if you are i think your best bet would be a pair of 400's or you could use a light mover.. that may be just the ticket for what you have in mind.
a hps 600 is good to about 4-5' room but 9' is way too much space for the light to get to.. and if you are not gonna use the whole space you hava to think about how you are gonna stop the light from leaving/entering the flower space or you will get hermies..
just the thoughts off the top of my head man.
hope this helps you in your search for 'free' meds
-J