Yes, your transactions have definitely been done after September 1st. However it is not too bad, maybe you may get a bonus for the upcoming airdrops.
I don't think there will be another UNI airdrops because so many people are now using UniSwap, but I'd like to see another exchange like UniSwap we need more decentralized exchange now, I have this feeling that Decentralized exchange and Decentralized Finance is going to be the next big thing, and people will start to adopt or embrace it.
You're a bit late with the party because DeFi hype now is already decreasing and also we dont need to have lots of decentralized exchange. One or two would be enough i guess.
When it comes to that airdrop, it wont really be something that will really be announced, just like on what happened with that sudden 400 UNI airdrop which havent been anticipated
and people who did make use of it wasnt expecting for some good freebies later on.
Mentioned above about message platforms or announcements havent been done.So we cant tell if theres a legitimate airdrop incoming or just some rumors.