What PAbaseball says.
HA D1 includes Ivy League; they start recruiting in fall of junior year (or just before that). Also schools like William and Mary. If that's what you're looking for, he should definitely try to take the ACT now, i.e. before baseball season starts. ACT/SAT are given on Saturdays, and depending on your baseball schedule, many in the spring will not be possible. And in that case, yes, Headfirst this summer is a great option. You can look at Headfirst's website and see all the schools that will be at each of their showcases; only go if there are schools of potential interest to your son.
PBR's showcases put your numbers online for the world to see, and they can also have pretty good local exposure, especially the spring events.