Flush? At 8weeks or let this plant go to 12 weeks??

Yeah those are just calyxes - seeds will grow in them if pollinated, but I doubt that’s the case. That’s what you want is to wait til there’s more visible buds/calyxes and those pistils/stigmas are less predominant. Autoflowers are wonky and I’ve rarely seen one actually flower in 8-9 weeks. I’d say you should shoot more for the 11-12 week mark as far as a chop. My autos often ended up (I rarely run them anymore) less dense and more airy. So I would say letting them go a bit longer should be better to help tighten up the flowers. That is the downside of autos, among many, that they really don’t get you to harvest quicker. Most guys I see end up running them 10-14 weeks. You can get FAR superior bud from vegging a photoperiod for 4 weeks and sending to 12/12. On that schedule you’ll have a harvest in 12-14 weeks. I digress tho - just my experience from starting off doing autos and then going to photos. I say let her ride tho for at least 2 more weeks