9 meters is just the cell length.
The size for the system is actually more than 10m including support and mounting structures underneath the cells.
Depth seems inadequate in the fore cell farm to house anything thats 10m deep, since they are still in the bow of the ship.
View attachment 101346
(Assume those people to be 1.75m tall, you'll need the depth to be 6 of those people stacked on top of each other)
Also, regarding 052d, its fore cells are placed longitudinally, so the outer cells are still within the central portion of the bow providing enough depth. Whereas 055 cells are placed beam wise, meaning the entire 8 cell structure will be just as long as the shallowest depth that is allowed.
Or maybe I'm just wrong.