Despite my confidence when growing years ago, my biggest disappointment was when I grew and dried out my 1st bud. It looked great while growing, greasy/stinky...looked great. The problem was that I only got 1 or 2 larger buds off of it, and when they were dried, they were 1/10 of their original weight. 35 years ago an old hippie showed me how to grow indoors with 5 things...a MH light,
Promix, 5 gallon buckets, and regular Loews/Home Depot Jack's 20-20-20 fertilizer (although they didn't have Jack's back then, it was Peter's), and that was about it. I grew plants 12 ft tall in 3 months indoors, and got buds 18" long and very thick. What I found is that a bright light is important. A 9 watt LED is fine for a houseplant, but if you are planning on supplementing your stash, you are going to have to get some stronger lights. I know that you are trying to prove that less powerful LEDs will work, but the less light energy a plant gets, the slower and smaller it grows. There is only so much energy that a plant can get from a 9 watt LED, so it compensates by growing as much as the light's energy allows.