They are exactly the same size one is just black nickel coated rather than standard nickel coated. The is no performance benefit from the black edition it just looks cool. If you want better performance then the TRUE Copper could be for you but it costs a small fortune ~£75 so any gains are probably not worth the extra expense.
Back to fitting in the case, I have no doubt hat the TRUE would fit in the 900 but each motherboard is slightly different so just because somebody else could fit duel fans would not guarantee that you would be able to if you are using a different motherboard.
By all means give it a go