As a signed route, the southern terminus of SR 9 is at its junction with US 231 and SR 21 at Wetumpka, and the northern terminus of the route is at the Georgia state line east of Cedar Bluff, where the route becomes State Route 20 (SR 20).

US 331 enters Alabama from Florida near the border town of Florala.

The route is one of several routes used to connect Alabama and other northern settlements with the Gulf of Mexico beaches in northwest Florida.

From the state line to Montgomery, US 331 and SR 9 follow a north–south orientation.

North of Montgomery, SR 9 as a standalone route assumes a more northeast–southwest orientation, and passes through rural areas and small towns in the eastern part of the state.