Scale question in regard to chord memory

I was playing around with a m9 chord on a chord memory function and proceeded to harmonize it with a bass riff and a lead sound, dunno whether it's important to mention the notes I have stressed with the other parts yet as I wanted to know how to interpret what's going on from a harmonic/scale related perspective.



I'm playing a descending Am9 to F#m9 to Dm9.



The Am9 and Dm9 fit the C scale/A natural minor but obviously the F#m9 chord is a fair bit off on the circle of fifths with 3 sharps but I like the sound of it in between the Am9 and Dm9 but now I'm wondering just what scale I'm in.



The notes I used in the lead go up from D to E to A, then to D, & E in the next octave and then to C# just before the F#m9 chord comes in before dropping to A when the Dm9 chord comes in.



The bass is a sort of ostinato riff and I was trying to hit notes that would work across the 3 chords and used a combination of octaves with these notes: A, D, E



The way I'm thinking, is that for hamonizing, certain chord tones sound terrible so collectivelly between melody and bass, I'm using: D, E, A, C#. A sustained A note sounds quite nice constantly.



So thinking in terms of scale, am I in D major / A mixolydian mode or does the deciding factor come from chord tones?



Hmmm, I hope that makes sense, I'm confusing myself.

Scale question in regard to chord memory