The spacing of the pendants sounds pretty good. I'm skeptical that the little 4" models will look proportionate to the island, or cast enough light to work by, but that's probably not critical at this stage; it sounds like your builder just wants to install the rough wiring and ceiling boxes. As for can placement, many builders prefer to put cans out over the aisle spaces. While this does make exact fixture placement more forgiving, it also makes it inevitable that your own body will cast a shadow over the area of counter where you're working. I'm of the 'directly over the counter edge' school of thought. This prevents such shadows, but also places noticable splashes of light across the upper cabinets, which makes it necessary to place these cans especially carefully. With 9' ceilings I'd probably use 5" or 6" cans, shoot for about 4' spacing over the counter edges, and plan to use 75 watt, 40-degree floods.

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!

I think slender buffet lamps on each end would look great! I say no pendant lighting..that way it will look unique and not like a residential kitchen. I love these metal finish lampswith matching metal shade from Restoration Hardware..offered in 4 finishes...

Thanks all! Island dimensions are 4' x 3' and I am considering a Pottery Barn glass schoolhouse style available in 8" diameter/7.5" height. Fixture is also available in 11" size. Both are 75 watt. I need more light than one fixture can provide. I would prefer 3 lights but that may be too many for the 4-foot length. Seems that 3 lights would have to be hung about 12" apart and that might seem crowded with an 8" fixture. Thoughts?