When to attend Headfirst showcase?

The harm in going this early is that he will almost assuredly be a better player in a year or two and, thus, show better at this key target showcase.  D1's aside, most academic schools don't recruit that far in advance.  He can attend a few local showcases to get him acclimated to the process.  Have him focus on continuing to improve his skills, game and conditioning (and his grades, of course) and hit the key showcases after soph year. 

Between now and then, you will likely find the school search becomes more focused and he learns more about what kind of player he is/ will become.

Getting good instruction and playing competitive baseball are more important at this age.  Depending on his physical maturity level, he is barely old enough to begin a good strength and conditioning program.

Even though cost is not an obstacle, I'd really wait until Summer after Freshman year at the earliest.  Some would even consider that early, but I think it is perfect.  I was in a similar situation and took my 2016 last Summer (so, Summer after Freshman year) and he was still one of the youngest there (easily).  I even called HeadFirst and asked their advice.  They told me that he would be in a very small group of 2016s attending (like 10% of the total?), but that "it would be good to get him the experience."  He has very good size and showed very well and got his name out there, but so many of the academic schools (Ivies, etc) recruit so much later in the process (lest they waste time on kids whom they can't get through admissions) that they cannot afford to spend much time looking at even rising sophomores.  They are more focused on rising seniors and maybe some juniors.  So, if you are willing to go out on a limb and trust a guy you don't know, save yourself a lot of time on the research of this and go summer after 9th grade.  You should also look into PG Academic Showcase in early June after his Freshman year.  To give you a sense of the numbers at PG Academic - these aren't exact but close - there were something like 130 kids there and my son was one of about 9 rising sophomores.

Read the threads about what's involved in committing and acceptance to Ivies and academic D3s. It seems to me since acceptance is as much about grades as anything else these schools are all about talent level after junior year. But summer after soph year would get him on the radar screen. If you want him to get showcase experience find a local college program who does an inexpensive showcase format camp.

Son plays at top academic school.  He did Rice's camp as a rising sophomore and didn't do HeadFirst and PG National Academic until he was a rising senior.  A high academic college camp, (like Rice, Dartmouth, Columbia, Williams, Amherst Swarthmore), at $250, is a great way to learn "showcase technique" and get some idea of talent level,required to play at the level.  As a rising senior on the academic showcase circuit, money will come flying out of your pocket.  Don't waste it now when its not necessary.  The coaches have their hands full with the pressure to see hundreds of rising seniors.  Freshman are invisible because they don't even have a PSAT score to talk about. Just my $.02