Mini Stars are types of items appearing in Mario Party 9.
Like the original stars, these items are collectibles on the board which tallies up to the player's total amount of one to determine the winner of a certain game and are used as a currency, like coins are. Their anti-counterparts are entitled Mini Ztars, deducting the amount of Mini Stars from one's scoreboard.
After a minigame, Mini Stars are given out to players in the various place. The higher ranking, the more Mini Stars gotten. Mini Stars are also given out to the winning captain from his/her current turn. They are also found on their very own Mini Star Spaces commonly appearing from Lucky Spaces. On a board, they can also be collected in groups of three, five or ten. They can even be gotten in a certain event.
After a board play, these items are converted to Party Points, but aren't when added as a handicap and the Party Points are rather deducted. Five bonus Mini Stars are also given afterwards as Bonus Mini Stars for each player. This also happens in the story mode, but only after Bowser's Station.
In the Solo Mode of the game, Bowser and his son Bowser Jr. have stolen all of the Mini Stars to put them to "good use" as they say. Players all start fighting one another for the Mini Stars to be collected.