Hawaiian pidgin math says; 36 no gozintas 9.

Not really sure what you are asking here.
You only have 9 square feet, and not much headroom.
5' max height with the lamp and clearance.
If you cram 9 plants into that space it will be very crowded.
I would not try to raise more than 5 plants in that space.

So, what am I missing here?

Aloha and good luck.

Weezard