Here is the full list of all 18 Grow Up achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Complete the game 100%
Rescue MOM
Complete all challenges
Collect all crystals
Discover letter block P
Unlock all seeds
Flower all STARPLANTS
Unlock all Telerouters
Take a Critter to the moon
Ride two Sporchids simultaneously for 400m
Blast a Critter 100m
Discover the bull and the sheep
Bounce on a Youch 7 times without touching the ground
Orbit the entire planet in BALL mode
Complete a challenge holding a Critter
Plant 10 Champolines on top of each other
Visit all biomes
Throw 100 seeds whilst gliding