I doubt that the Ojai Valley Inn and Spa is directly managing a kayaking day trip. I suspect they are subcontracting or referring you to a licensed tour company, such as Paddle Sports. Look at Island Packer's website for more information: http://www.islandpackers.com/watersport.html

You can manage to kayak without a wetsuit in July - just don't fall out of your boat. If you want to snorkel you'll be much more comfortable in a spring wetsuit.

I realized you are probably saying that the Ojai Valley Inn is including transport from the Inn to Oxnard Harbor. This is probably all they are doing in terms of conducting a tour. They would have to pass you off to a licensed tour company, to give you the actual kayak tour. So, I think booking through the hotel makes sense. They appear to be offering the shuttle service to the harbor, which might have been available, for free, whether you make the arrangements yourself or not. Is that the case?

Not providing wetsuits for a tour group is strange. That is nearly always an option, and it just may be that they didn't bother to mention it, or it may be how they are compensating themselves on their cost.

It would be the Ventura Harbor or Channel Islands Harbor (not "Oxnard," thouch that's where CI is located). Frankly I would rent a car and book directly. It's an easy drive from Ojai even if it is on the other side. Much easier than the drive we made from Edinburgh to St. Andrews in a snow storm! Or hire a limousine, the pound is so strong it will be cheap.

And you'll need a wetsuit, make sure it's included.