Hi, Fong. I meant a 9th, as in dom7 with a 9.
Above is a blues improv I played just thinking chords. Not pentatonic, not blues scales, not mixolydian ... none of those. I was seeking out a bluesy melody, coaxing it out of the chords as I went. I haven't checked, but I'm sure I played every one of the 12 notes available at some stage or other. I don't ever want to restrict myself to a scale or mode when in fact all 12 notes are there to be used. This is why a long time ago I stopped bothering with the notion of scales. Melody is what I'm interested in, and I find it outlined in the chords. Once you have an outline, you can then embellish till the cows come home.
Below is another, this time a jazzier tune. Again, all the lines came from the chords. I'm not sure how you'd negotiate such a progression thinking scales. Scotty_b said he'd do a modal approach, but if and when he does (Scotty?), I guarantee it will also be following the chords. So whether you consciously bring modes to mind after studying the chords and play them as modes, or simply let each chord
be the mode, chords are boss. But, I'm always open to be proved wrong. I can load the backing tracks of those two tunes if you'd like to have a go in a scalar fashion.