I would add some sand, personally. It gives the same ease of maintenance as bare bottom, but looks much better IMO. Also, if you were to use sand you could try real plants.
As for stocking, I would reccomend 1 Jag (probably best female). Some may say 2 Oscars, I would personally only say 1. Or you could likely have 2, possibly 3 EBJD's.
I know it seems a waste to only have 1 fish, but Jags and O's are both large, bulky, messy eating fish. Which are also very active.
Regardless of whether you raise juveniles, cichlids are cichlids and can turn at any point, and with only 90g it wont be pretty.
Anyway, nice looking tank, I'm sure you can do a lot with it. I would recommend aquascapingas I personally cant stand bare tanks.