Do you have a bounty program and do I need to go through KYC to join it?

I think it is still possible to join, join this group and ask there - https://t.me/CSBounty

Did they announce up until when it will last?

I think they are really flexible with this, maybe they wan't to see how the market will react and the decide.

You're probably right. But then - do they increase the pool?

They should probably increase it if they plan to prolong it for a longer period.