A 4/9 @ A-5. A4's punt is not blocked and crosses the neutral zone.
Legacy gave you everything you were asking about. But, just know that "blocking" of the kick has no bearing on anything. Understand that, by rule, blocking is ANY amount of contact with the ball. So, whether the ball just grazed a B player, or a B player deflected it such that the ball does not cross the NZ, the "blocking," itself changes nothing. It doesn't even count as "touching." If, thereafter, the ball remains behind the NZ, either team may catch/recover and advance the ball. However, if, after being blocked, the ball manages to cross the neutral zone (in flight, bounding, or rolling), then rules change. Team A are not eligible to touch the ball, unless it is touched by Team B. Regardless, the ball is dead when possessed by A, and Team A may not advance the ball.
Perhaps the toughest thing to explain to Team A would be why the result is a safety, even if the ball was muffed by Team B (no new impetus) beyond the NZ and traveled back into A's end zone, where a Team A player recovered it. The impetus is still from A's kick, so, the ball is dead behind their own goal line, and they are responsible for the ball being there. That's a safety. "But they touched it!" Yes, they did, Coach. Still a safety - 2 points for B. Get your kickoff team ready.
There is no such thing as "partially blocked," as far as the rules as concerned. It is either blocked (touched by B - any amount) or not. We don't really care. What we care about is what happens afterward.
I will expound on one other point. If B20 bats the kicked ball in A's end zone, and it travels into the field of play, and then, somehow, travels back into A's end zone where it goes OB or otherwise becomes dead still officially in A's team possession, that would yield a touchback, because the impetus is now from B20's batting (since B20 caused the ball to travel from the field of play across the goal line). So, Team A would decline the penalty for B20's batting foul, and take the ball at the A-20.
If B20 does that, I would imagine his teammates (and coach) would want to kick his behind. Just fall on the frickin' ball for a TD, ya moron.