9 gauge aluminum refers to aluminum plate metal of a specific thickness. Instrumented measuring systems are commonly used to determine the thickness of metal sheets, including aluminum. In this system, a higher gauge number represents a thinner sheet, while a lower gauge number represents a thicker sheet.
The thickness of gauge 9 aluminum plate is approximately 0.1144 inches or 2.90676 mm. Note that actual thickness may vary slightly due to specific manufacturing tolerances and standards.

This specification of aluminum plate has a balance of strength and flexibility, making it suitable for a variety of applications. Here are some of the key features and uses of 9-gauge aluminum:
Strength and Durability: Although 9 gauge aluminum sheeting is relatively thin, it is strong and durable. They can withstand moderate impacts and provide structural integrity in a variety of applications.
Lightweight: Aluminum is known for its lightweight properties. Gauge 9 aluminum plate has a good strength-to-weight ratio, making it ideal for applications where weight reduction is a priority.
Corrosion Resistance: Aluminum naturally forms a protective oxide layer, which gives it excellent corrosion resistance. This makes Gauge 9 aluminum suitable for use outdoors or in corrosive environments.
Formability: Aluminum is highly formable, meaning it can be easily shaped, bent, or formed into different configurations. No. 9 aluminum plates can be manufactured through processes such as cutting, bending, welding and stamping to meet specific design requirements.