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%
Complete all challenges
Collect all crystals
Unlock all Telerouters
Bounce on a Youch 7 times without touching the ground
Orbit the entire planet in BALL mode
Throw 100 seeds whilst gliding
Ride two Sporchids simultaneously for 400m
Discover the bull and the sheep
Discover letter block P
Complete a challenge holding a Critter
Take a Critter to the moon
Blast a Critter 100m
Plant 10 Champolines on top of each other
Unlock all seeds
Rescue MOM
Flower all STARPLANTS
Visit all biomes