The Mewtwo (9 / 16) card can be found in the Pokémon Rumble set.
Recently sold 4 times and based on those sales is worth around £40.60.
Currently, there are 3 open listings for this card on ebay.
This card sells in the range of £27.03 to £54.17, making it quite volatile.
This card was illustrated by Pokemon Rumble.