Did you say you are feeding from the bottom? Or are you using the typical in water line at the top of the bucket that sprays on the medium? Remember you need some sort of way to keep the grow medium wet and encouraging root growth. Once its all established then it is of less concern.

Maybe I just misread you. Remember, when recirculating DWC is done correctly it is explosive, so with 9 plants and only 1 light, I would veg for less then 2 weeks. Maybe longer if its your first time but be careful. They will quadruple in size.