Will 9 inches of water take longer to freeze than 6?

Yes, 9 inches of water will generally take longer to freeze than 6 inches, primarily due to the greater volume of water that needs to lose heat. The thickness of the water layer affects how quickly heat is conducted away from the water, and a deeper layer has more thermal mass, which retains heat longer. Additionally, ice formation typically begins from the surface, so a thicker layer delays the freezing process from reaching the bottom.