Re: First boat for small 9 yr old girl?
Watch Craigslist. With enough time you'll find an El Toro or Opti in your price range. You could make an El Toro too.
I have a Dyer Dhow Midget that was a little more than $500 and would be good for a kid to sail in, though it won't sail as well as an El Toro or Opti. Just keep an eye for all dinghies with sail kits. I see one or two options in your price range go by Seattle Craigslist every month.
boats that I sail on regularly: Pearson 28-2, Rondar 505, Yankee 30, Blanchard Junior