The Avia BH-9 was a one-seat sport aircraft built in Czechoslovakia in 1923, based on the BH-5. As with other developments in the BH-1 lineage, the BH-9 was a low-wing braced monoplane that accommodated the pilot and passenger in tandem, open cockpits. The BH-9's structure was strengthened to allow for the use of a higher-power engine than in its predecessors, and for the first time, this was a domestically-produced powerplant.
The Czechoslovakian Army showed interest in it as a trainer and liaison aircraft, and ordered 10 examples under the designation B.9.
A B.9 won the 1925 Coppa d'Italia air race, and the following year, one was flown on a 1,800 km (1,100 mi) circuit Prague-Paris-Prague with an average speed of 131.2 km/h (82 mph).