You are very fortunate to live in Virginia. There is no harm in applying for merit at schools such as Duke, Vandy etc…but keep your expectations in check. Admission to these schools is tough even for outstanding students like your S…merit is even more competitive. I do not recommend ED.
How much can you spend on college each year? You might want to look at honors colleges at schools such as Pitt and the University of Maryland. Schools such as Alabama would also give him merit. Some other schools include Lafayette, Lehigh and the U of Miami (I know equally strong students at all three of these schools who received merit…I would investigate). Your son would need to show interest at Lehigh, but they are looking to increase geographic diversity.