"set up" I'm pretty sure Miles called it a set-up chop block or something like that. It was clear Sam was reaching his hands forward towards the lineman and never saw the back coming to block him low.. I'm not sure what the exact meaning of engaged means but from memory it seemed like Sam had a hand on the lineman.
I had trouble understanding too. However, when he references the 9..9, I believe he is referring to his jersey number, 99. The reck and Jared, I have no idea...