BE CAREFUL w/ the ol' "home-made" foliage spray! Easy to burn your plant (spraying hi N fert on it).
Just find a soluble fert. w/ a higher N value on it. Yours is 9, you said, so try to find one w/ 15 or 20 even. Then take baby steps w/ it. Start your plant out on a half strength watering. If she responds well to that move up to 3/4 stregnth and so on.
But really, in all honesty, the plants don't really look that bad to begin w/. Sure they're a little lighter grenn than some strains, but they look like a sativa dominant strain anyway. Indicas get darker because they're genetically adapted to becoming that way so as to increase their "self-warming" ability: Darker colors get warmer quicker. Indica's are adapted to colder climates.
Anyway I'm rambling now.
My point was......your plants seem to be ok, but if you'd like to try to "darken" them up a little you could increase the Nitrogen level they're getting. but be warned that you could fuck up a good thing!
You know what they say about "if it aint broke......."