A 9” cake pan has about 25% more capacity than a 8” cake tin. So the cake batter will be more dispersed in the cake tin. The metal and any coating on the cake tin plays a significant role in how quickly the cake batter bakes. Dark metal, non stick coating, anodized aluminum conduct heat intensely. So these types of cake pans will bake a cake faster. If you have these types of cake tins, reduce the taking temperature to 325°F, then start checking the cake 10 minutes before they stated time.
Understand that using a larger pans means the cake layer will be about 1/2” high, 3/4” at best.