http://professionals.collegeboard.com/testing/sat-reasoning/register/special/8th-grade This explains the procedure for asking the scores to be saved. If you want to keep them you need to make a request in writing soon otherwise they will be lost.
It is pretty common for 7th and 8th graders to take the SAT so admissions wouldn't be surprised to see those old scores there later. Most students don't need to keep them, but they may come in handy if your child ever considers dual enrollment or early college classes.
Also, SET is something worth considering.
http://cty.jhu.edu/set/index.html
