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