If you think pendants will look funny, recessed fixtures aren't your only option. You could go with flushmount (two?) or semi-flushmount fixtures (pendant hung really close to the ceiling end up looking like semi flushmounts, anyway). Or you could go with some kind of track (see link below). Here is a link that might be useful: Track light example

For a small area, kitchen, two pendants are enough to illuminate the room, and there would be overwhelming. Since you have a 9-foot ceiling, the pendant should hang 15-23 inches below.

I had this exact same issue when I started designing my kitchen a few months back. My island will also be 6.5' long, and I ended up drawing the setup in autocad with the dimensions I was interested in. I ended up settling on the configuration in the image I attached. The island is 6.5 long, and the pendants are 14" in width. I think ultimately there's no right answer in a vacuum, depends on the other elements in your kitchen. Our island sits prominently in the middle of the kitchen and is the focal point when you first walk in. Our cabinets are also very simple, done purposefully so we could go a bit more extravagant on the finishing details including islanding lighting, hardware, and faucets. We played around with lights bigger than these and it didn't look right. We also played around with 2 light setups and it felt off to me. Good luck with what you choose!

Nope, no one that I know of has ever bumped their head into the deeper upper cabinets. And part of them are over our prep sink where people normally would have no upper cabinets, or would have the upper cabinets raised higher over the sink section. We have 15" deep uppers over our prep sink (which is the sink I use most of the time anyway), 16" deep including doors. It is 18.25" to the bottom of our light rail (20" to the actual cabinet). I have never had an issue with it hitting my head or any other issues. I was nervous to do this over my sink, but went to see a friend in NYC during our build. He had no raised area for head room and there was no issue there either, so that convinced me it would be ok. I don't remember if his were 15" deep, or standard 12" deep. But he is over 6 feet tall. I am 5'3" and my hubby is 5'10". The left & right cabinets are 12" deep and 42" high. The middle two cabinets are 15" deep and 45" high.