To level up your Buildings from level 9 to 10, you will need a Divine Inspiration.
A Divine Inspiration can only be used once to upgrade a Building to Level 10. If you cancel this upgrade, you will receive your Divine Inspiration back. However, if you Destroy or Deconstruct a Level 10 building, the item will not be refunded.
After level 10, you will need to use Crystals. There are different Crystals in the game: