- "Hey! My name is 9-Volt! I'm the grade-schooler gone old school!"
- ― 9-Volt, WarioWare, Inc.: Mega Microgame$!
9-Volt is a major character in the WarioWare series. As an employee of Diamond Software (formerly WarioWare, Inc.), he creates a number of different microgames. As a self-proclaimed fanboy of retro Nintendo games, his microgames tend to be homages to these old games.
WarioWare, Inc.: Minigame Mania
9-Volt, along with Wario's other friends, are recruited by Wario to create a video game company called WarioWare, Inc.
In his story, 9-Volt comes home after a long day at Diamond Elementary. He decides to relax by mixing records with the help of a large, Game Boy-like machine. Doing this causes the Game Boy to grab a large cartridge, which triggers this story's set of microgames. After the games are completed, a reporter appears and announces the releases of the Game Boy Advance SP, causing 9-Volt to rush off to go buy one.
9-Volt also appears in the ending amongst the other employees when Wario takes off without paying them.
WarioWare, Inc.: Mega Party Game$!
9-Volt's character introduction is very similar to his stage in Minigame Mania, but the giant Game Boy has been replaced by a Game Boy Advance.
9-Volt is seen at school when a new student named 18-Volt is introduced to the class. The two become fast friends due to their shared love of music and classic video games. 9-Volt invites 18-Volt to his house, where the two stay up late into the night playing video games and loud music, until 9-Volt mother 5-Volt comes to tell them to go to sleep. However, 9-Volt manages to sneak his Game Boy Advance SP to bed with him so he can keep playing, but his mother catches him with that too.
9-Volt's story opens at the Toy Express store, where a new video gamed called 36-Volt Man has just been released. After getting a copy, he rushes home with 18-Volt, where the two spend the whole day and night playing the game. Afterwards, they celebrate their session by mixing records (which triggers this stage's microgames) until they finally pass out from exhaustion and go to sleep. However, this late night gaming session makes them late for school the next morning, and the two have to rush off.
WarioWare: Smooth Moves
In WarioWare: Smooth Moves, 9-Volt and 18-Volt are once again having a gaming session, when 9-Volt shows off a classic Game & Watch (specifically Donkey Kong). 18-Volt gets over-excited and tries to take it from 9-Volt, accidentally snapping it in half. 9-Volt gets very angry at his friend for this, kicking him out. Later, when 9-Volt goes to a classic video game store to purchase a replace Game & Watch, he finds that 18-Volt has come to do the same, and forgives his friend.
In WarioWare Gold, 9-Volt's appearance has changed like other characters. His hair has grown. He is in the "Touch League". His microgame genre is "Nintendo Classics". 9-Volt complains about math. He realizes that Fronk spoke. He mentions that they are not allowed to have pets in school. Fronk denies that he is a pet, but he worries he hates maths. Fronk helps him with equations by using imagination. 9-Volt imagines bigger that he is in an RPG game. After the gameplay, he thought maths was fun and called Fronk his "apprentice". He decides to give Fronk his dessert later that night; but Fronk mentions he is too old and turned "1" year old. Fronk mentions his "8-bit yoga".
He appears in 18-Volt's cutscene and the gameplay. In the Potluck Gang, Red brought fresh oysters and Orbulon brought carotene logs that are "radioactive", but 9-Volt was skeptical. Ashley brought a "mandrake root" and he thought that potluck was a bad idea.