The Search for WondLa by Tony DiTerlizzi

Eva Nine had never seen the actual sun before, or walked outdoors. In fact, she had never even seen another living person in all twelve years of her life. That changes when a marauding huntsman destroys her underground home and sends her fleeing for her life. She is desperate to find someone else who is like her, and a single clue gives her hope: a crumbling picture of a girl, a robot, an adult, and the word "WondLa".

Matches:

Timeframe: published in 2010
Small, electronic home: "underground Sanctuary"
Robot maid: "Muthr"
Slip of Paper = Wizard of Oz: YES
Alien companion: YES
Human boy comes to take her home at the end: YES

The Search for WondLa by Tony DiTerlizzi

Eva Nine had never seen the actual sun before, or walked outdoors. In fact, she had never even seen another living person in all twelve years of her life. That changes when a marauding huntsman destroys her underground home and sends her fleeing for her life. She is desperate to find someone else who is like her, and a single clue gives her hope: a crumbling picture of a girl, a robot, an adult, and the word "WondLa".

Matches:

Timeframe: published in 2010
Small, electronic home: "underground Sanctuary"
Robot maid: "Muthr"
Slip of Paper = Wizard of Oz: YES
Alien companion: YES
Human boy comes to take her home at the end: YES