We will arrive in Paris at CDG and then depart from Beauvais airport 9 hours later. We think we will rent a car to get between airports and sight-see along the way. Any suggestions
You could visit the medieval walled town of Senlis and/or Chantilly.
You think you will rent a car. Have you priced one by the day? I have heard that some agencies are renting by the hour. You might ask about that when you find out how much the daily rental rate is. Also ask if there is a drop charge at the other airport.