You read correctly, a nine-speed automatic is under development and headed for upcoming Merc transmission tunnels. Reports by Autocar say the gearbox will be mated mainly to larger cars and engines in the Merecedes-Benz range.
Mercedes-Benz claim using nine speeds dramatically improves fuel economy as the engine power and torque is spread more evenly rather than the engine pulling longer gears.
It is quite a bewildering amount of ratios to fathom, is it too many? Mercedes has said nine is the maximum number of cogs physically capable of fitting inside a passenger vehicle gearbox though, so there's a sign of limits ahead.