D1/2 coaches can contact 8th graders because they are not yet “prospective student athletes.” See 13.02.13 Prospective Student-Athlete. (“A prospective student-athlete is a student who has started classes for the ninth grade. In addition, a student who has not started classes for the ninth grade becomes a prospective student-athlete if the institution provides such an individual (or the individual’s family members or friends) any financial assistance or other benefits that the institution does not provide to prospective students generally.”).
When in doubt, check the NCAA rules. Each division defines “prospective student athlete” and informs what contacts can happen, when and where.
Start now. Go to the D1 ID camp. Expect nothing, but go to learn. I always quibble that the ID camps are not money makers, but rather fund raisers. Do they make money? Sometimes. Do they lose money? Maybe. The college camps are a bit different from those put on by independent groups that had better dang sure make money or sooner or later they will go out of business.
From a coach’s perspective, if you have a couple of potential recruits that you are really looking at, you need to have enough players to make at least two teams and most likely much more. Accordingly, generic invites by email or mailing are not true “invites” - they are designed to get warm bodies to the pitch. A true “invite” may be given a promo code with a discount to the camp or have a coach personally reach out to the athlete. Chances are this happens only in the rarest of cases with 8th graders.
Good luck and enjoy the process.