I would try appealing--what will it hurt? It can be frustrating for you, but if you feel he should be in there, try it. They can only say 'no' again. Maybe have them look at that unfinished creativity test, if completing it would've put him over the top.
Definitely test again next year, for sure. My 12yo who is totally PG, just beat out the average high schooler on the SAT by a couple hundred points, qualifies for SET, etc, did NOT get placed in the gifted program in our old district on her first try. I have no idea what her scores were because all requests were met with silence from the district. The next year scored 99% on the CoGAT and ITBS, tested one year ahead of her grade. I think the only real difference was how well she focused on the test, and her experience with formal test-taking.
