You both ave 300 - 500 items and are selling cloths and jewelry. This is a field that is getting flooded from Chinese sellers. Q2 eBay lost 2% of their buyers and gained 5% more sellers, guess where those sellers are from? Anytime there is a hit on the market or a troubling time, or anything else, jewelry and clothing will get hit first.
I sell auto parts and I have never done as well as I am now, selling sometimes 30 items a day, but of course I have 3000 items listed and I list 200 items a day which is a bit more than 9. I don't even think 9 is enough to trip any positive benefit from Ebay's Casimi or whatever they call it, it's just not enough.
Sometimes when you're a smaller seller it's almost as if ebay is a running faucet, and someone at sometime for some unknown reason turns it off, and then your sales dry up. Some people say it's because ebay has too many products and is giving someone else a chance. Most people claiming this say things go back to normal eventually.
If your impressions dropped suddenly as you say it does tend to make you believe that it's something ebay did. They might be messing with categories your items are listed at, or tweaking casimi (whatever their SEO engine is called) and whatever they are doing is not good for you.
