I was wondering...

The Bermuda Cubes have six diferent pieces, right?

Would be possible to exchange pieces between two Bermudas to make a third Bermuda?

or

There is any valid combination that would create a 9th Bermuda Cube?

Pluto for instance?

Yeah, you can swap pieces between bermudas. I bought a Venus (fishered) and an Earth. From those two I could make:

-Mercury (fishered or not)
-Venus (fishered or not)
-Earth (duh)
-Mars (not the same triangle configuration, but three triangles not around a corner)
-Jupiter/Neptune (also not exact replicate, and sticker cutting is required, but three triangles around a corner)
-Saturn/Uranus (also, not exact replicate, and sticker cutting is required)

In short, all the other variants.

Solving wise only the amount and location of the triangles matter, not their orientation or if some faces happen to be fishered or not. So in a way the Bermuda series only has 6 different cubes, Jupiter/Neptune being twins and Saturn/Uranus as well. So there really isn't a ninth planet to be discovered.

I quite like them, fun to solve and not too hard. My personal favorite is Mars, or Earth perhaps. Haven't solved the 4-triangle cube yet though.