Different strains will mature at different rates. I had the orange/brown hairs you're talking about but my tric's were not clear so I let it go, a few years ago I probably would have pulled them based on the hairs. It's possible they needed a few more weeks to finish.

One 400W for 9 plants could be part of the problem as your lower branches aren't getting much light. You may want to try growing a few plants larger as their light needs won't be the same as 9.