The Yakovlev Yak-9B was a modified subvariant of the Yak-9D, which was the third variant of the Yak-9 fighter aircraft family. The Yak-9B was a fighter-bomber configuration of the Yak-9D (factory official designation Yak-9L) with four vertical tube bomb bays aft of the cockpit capable of carrying up to four 100 kg FAB-100 bombs or four PTAB cassettes with 32 1.5 kg bomblets each, though only 200 kg of weapons were normally carried. The Yak-9D was a longer-range variant of the standard Yak-9, with a fuel capacity increase from 440 to 650 litres and a maximum range of 1,400 km. Since the Soviet Army went on the offensive in 1943, covering operational advances from the air required an increased number of fighters. The Yak-9D underwent modifications to produce the Yak-9B, which could carry bombs, but this modification did not result in mass production as the Yak-9B armed with bombs had poor manoeuvrability, limiting its combat effectiveness against other fighters. Furthermore, the lack of bomb-aiming equipment made bomb targeting inaccurate.

Introduced in Update 1.53 "Firestorm", the Yak-9B is the only Yak fighter aircraft with an internal bomb bay. Players can experience the Yak-9B's unique design of being able to ground strike as well as compete for aerial supremacy against adversaries. This is very useful in ground realistic battle mode. Playstyles are identical to those of other Yak families, with the exception that manoeuvrability is slightly reduced when armed with bombs. It remains on the low-altitude spectrum for best performance, though the engines are slightly more powerful as compared to the Yak-1 variants.