We had a lovely meal at Via Napoli during a visit last December and it is now on our "must do list" each trip. That being said, and keeping with the real Italian tradition, the meal was served at a much slower pace than other WDW restaurants. Our server was extremely personable and laid back. He encouraged us on more than one occasion to slow down, enjoy our entrees, and make the whole meal a relaxing experience. What an pleasant and unexpected change to the normal "rush you out" mentality to turn over tables we normally experience at WDW. We were so pleased with the overall experience at Via Napoli, we made sure to seek out and notify a manager of our satisfaction.
To try to answer your question, it is quite possible to still see the beginning of Illuminations at 9:00p. I would highly suggest you arrive earlier than normal in an effort to gain seating prior to 7:45p.