I'd venture to guess that you food was a little on the low side which caused your plant to draw from it's self for food in the end here. At 9 weeks, and judging by your leaves I'd say you have an indica leaning plant which in most cases finish in the 10 week range.
I think all you are seeing is what the Internet seems to call fade. Personally I call it starvation, but to each their own.
I'd get a pair of of scissors ready to go.
:farm:
No way, dude. I fed them too much if anything.