Mario Party 9 was announced during E3 2011 for the Nintendo Wii. It is the ninth game in the Mario Party franchise, the twelfth overall and the second for the Wii console. In this game, players can now play together on a car while roaming around the board. The game also has new boss battles, new minigames, and all new boards.
Like previous Mario Party games players move around the table top style game board by taking turns rolling a dice. The big difference from previous games in the series is that players do not move around individually on the board, but instead move around collectively in a car. This car takes all of the players down a linear path, instead of around a large cyclical board. At the end of every board is a boss battle, which essentially takes the form of a slightly longer minigame.
Instead of using coins to buy stars, this is the first Mario Party game where every player earns "mini-stars." These are a currency that is used to buy everything during games. Winning will earn you "Party Points," which allow you to unlock stuff in the game's Museum.