Here is the full list of all 9 Son.Light.Sleepwalker achievements.
You successfully got the boy back to bed for the first time.
You spotted the bear for the first time.
Got him back to bed with his bear.
You saw the music horse and didn't mess your pants.
You met the psychologist.
You launched the drone.
You made it to the birthday party!
No door can stop you!
You got him back from the kitchen.