The Newport area is great for kids. In addition to Ripley’s, there is also Undersea Gardens and Wax Works wax museum on the historic bayfront and the fabulous Oregon Coast Aquarium on the north side of the bay. The Yaquina Head Outstanding Natural Area is a great place for all ages. It’s a good place to spot harbor seals, observe bird life and it has a vibrant tidepool area accessed by stairway, so plan your visit for a low tide.
On the way to or from Newport you could include Seaside on your itinerary. It is the Coast’s most family friendly city with many family attractions. Your nine-year-old would likely be most interested in the large arcade (Funland), bumper cars, perhaps the indoor carousel and, for sure, the many candy stores. You can feed seals at the small and classic Seaside Aquarium, a much different experience than the elaborate Oregon Coast Aquarium in Newport. You could then enjoy a scenic drive along the coast to Newport.
If you have the time, you could also consider traveling further down the Coast to Sea Lion Caves in Florence. Newport to Florence is a beautifully scenic drive.