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