How fast is Haru? That explosion feat can't be measured very well since the speed of the explosion is unknown, and it looks like Haru started moving before the space exploded (in other words, he dodged the opponent's aim and reaction speed more than the explosion itself).
Also, please don't say "he's gotten faster." Dark Schneider got faster during the course of Bastard!!, and Ichigo got faster during the course of Bleach. Just saying "he was X fast in an early volume" doesn't mean anything at all, except that he is as least "X fast."
And don't underestimate the speed of 666 Satan characters. Both Jio and Cross were able to keep up with Michael, who was able to dodge an enormous cloud to ground lightning bolt with ease:
Anyways, going by the info they have on wiki, Haru should be able to take this match if Jio doesn't go all out. Jio would rather die than let Satan take control PTJ. Furthermore, given that Haru's final sword seals evil, Haru has a big advantage. One scratch could potentially end the match.
If Jio were to start in Satan mode though...can Haru tank or block one of Satan's 50 km annihilation blasts?