The advantages of meeting over a coffee are that it is quick, you're on roughly neutral territory, and there's an opportunity to feel things out enough to decide whether it's worth taking things to the next level both personally and technically.
Being able to concisely describe what you've done in the past, what you'd like to do in future, and why you approached the firm should cover the bulk of the work content. Having an opinion on related technology issues is good, and I usually ask semi-random questions outside of work stuff too, just to get a feel for the person: nothing too controversial, but just conversational. Even if you're interested in a purely technology role, demonstrating that you can talk to strangers doesn't hurt.
It could be a little as 15-20 minutes; it could last for hours. Be ready for either. CTOs are usually very busy people, so get to your points and don't waffle.
Try to pay, but don't insist. Thank the person for their time. Send a followup thank-you email (and do anything else you said you would too).
Good luck!
I'm not sure what you meant by "While their offering is an enterprise product, I liked the product and cold-emailed him seeking the position".
Maybe I'm reading to much into it. But you sound despondent about the prospect about working with an enterprise product.
If that is the case, remember, a job works both ways. It's not fair on yourself or the employer to work for something you're not truly enthusiastic about.
Good luck!
Expect two peers talking shop about the industry. Most likely it will be surface level stuff. Be prepared if conversation goes deep. A lot of guys like the informality of coffee chats hoping to foster a more genial conversation. Expect that he is going to size you up on potential cultural/team fit.
You can craft a great meeting by expressing genuine interest in him as an individual. Read his profile, look for points of connection. Ask: What were the attractors for him to join the company? What are some of the priorities he's facing now? Where are they struggling?