Lets see... the demensions of the grow box is 9 feet tall, 5 feet long, but only 1 foot wide. Is there enough room to grow a plant? I'm thinking a sativa strain would fit nicely, because it's so tall. Yet... can any strain really fit in a 1 foot wide area?
It is a little shallow, but it would work. Just get enough 1 or 2 gallon pots to fill it, and don't do any training to your plants. Let them grow straight up. A sea of green style grow would be perfect for that space. Any strain will fit, it's not like it has a choice. It won't do any damage to the plant, as long as there isn't any water sitting on the leaves for an extended period of time.
Obviously 5-6 max and you'll have to flip 'em when they're 10-12in...Plus you're going to have to pull them all out every time you water/trim whatever...If you flip at 1ft they'll wind up24-30in tall....