This jam track features the ii & V chords from the Key of A. Any scale patterns from the Key of A can be used to improvise over this progression. On pg. 57 of my "Guitar Visualizations" Playbook, I have diagrammed out the "5" positions of the Key of A. Click here to view or download the Key of A-Key of F#m page.
The B minor pentatonic scale is another choice as an improvising scale. You will notice that if you look at the 7th position scale from the Key of A and you take out the C# & G# notes you end up with a B minor pentatonic scale. On pg. 62 of my "Guitar Visualizations" Playbook, I have diagrammed out the "5" positions of the Bm pentatonic-B blues scale. Click here to view or download the B minor pentatonic-B blues scale page.
I have recorded "4" You Tube videos that feature various improvising strategies for this progression. The links to the videos can be found here - Bm7/E9 Jam Videos.