Here is the full list of all 9 Maui achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Gain the favor of Kane
Gain the favor of Ku
Gain the favor of Kanaloa
Gain the favor of Lono
Defeat your first enemy
Enter the Halau for the first time
Fulfill your kuleana
Plant your first taro
Find a strange island