Give each one what they need, below is a list of all the solution if you are stuck for the golden crown.

Round 1:
Girl: Slipper
Steel man: Heart
Scarecrow: Straw (hay)
Lion: Bold Jacket

Round 2:
Girl: Shoe
Steel man: Love
Scarecrow: Hay
Lion: Bold Shirt

Round 3:
Girl: Heels
Steel man: Cupid
Scarecrow: Brain
Lion: Bold Glasses

Scribblenauts Remix 9-9 Cheats Hints gallery:
9-9-1-a: They’ve come to see Maxwell. Give them what they need!
9-9-1-b: The girl needs something to wear, the scarecrow just wants to think!
9-9-1-c: The metal man wants to feel love, the lion wants to be brave.