Just to be clear, the money you put into a qualified 529 plan is after tax dollars, the only thing that does not get taxed is the gains on the investments, but only if they money is used for qualified educational expenses. Since we are talking about 9th graders here, I'm not too sure that investing 10k a year at this point is going to have huge tax benefits. However, if you have been investing in one since your children were young, then the tax benefits can be a lot greater.
To the #mykidsux guy on here that thinks he knows anything about college admissions...here is a news flash. If your child is going to go to a PRIVATE institution, that money in a 527 will go against any FASA or CSS aid. So if you are an average person and are looking to get some need based/merit based aid, they will subtract a percentage of the 527 out of aid. So have a little clue before giving out financial advice from ( I guess) someone that has not been through the process. Talk to a college financial planner.
