If they want to get in touch with you, they will. Whether it is thru DM, text, email, travel coach, carrier pigeon, etc. I'm sure having a twitter or instagram can help but almost all coaches are still recruiting traditionally. It seems kind of silly to make a personal baseball instagram to me but if you want to add some video to your twitter page and have the travel team he's on or whoever share it then go ahead it can only help unless the tweet below it is of him doing a keg stand.
It's not necessary and most likely nothing will come of it but most of his promotion should be done by others or via email. You don't really want to promote yourself on your own page really. Not a great look.