Until today I had a few dominant 9th arpeggios in my toolbelt but it never occured to me exactly how to use them. Romanes “l’Esprit Manouche” book mentions them as an important topic. I remembered back to a lesson that Rip McCollough gave me and he showed me a relationship such as this:

Upon very close inspection, you will notice that the Dm6 arpeggio is equal to the G9 arpeggio without the root. When you add the root note, as pictured, then you see that we have a perfect dominant 9th: 1st, m3rd, 5th, b7th, and 9th. Take out the G note and you have a Dm6 inversion (6th, m3rd, 5th, and 1st on the B string, as pictured in the left hand circle) and a standard Dm6 with root in the base (shown in the middle circle if you remove the G note).
Last December 24th, I talked about the Bireli style stacking patterns. One of these was the G pattern, as you see here:

|——————————–9-10-12-|-
|————————-7-8-10———|-
|——————-6-7-9—————-|-
|————-4-5-7———————-|-
|——-4-5-7—————————-|-
|-2-3-5———————————-|- G6/9b5
You will notice this pattern consists of 1st, b5th, 5th, 6th, 7th, and 9th. It is exactly the same as the minor 6th inversion I talked about above except there is a b5th instead of the 3rd and a dom7th instead of a b7th.
Why is the first arpeggio in the photo compatible with the G stacked pattern I just talked about? The answer is that the b5th note is merely a leading tension tone to the 5th and therefore a standard altered sound and perfectly legal. The dominant 7th note that it introduces on the other hand is probably pretty not as pretty but it does fit into G under the guise of the diminished arpeggio or whole tone scale.
I might be pretty confused here (confusing dom7 with maj7) but I am throwing this out there anyways. Feel free to correct me or email me some hints. Im not a music student, I just do this as a hobby, and so my ideas can be problematic.
The morale of the story here is that you need to learn you minor6th arpeggio patterns. They are essential.