What does ‘achy old pros‘ mean , and what is an allegory of ‘Old pros returns to holy rituals of this game (Super Bowl)?,

"Achy" (ay-kee) is the adjective form of "ache"; An "achy old pro" is a seasoned veteran of the game with many minor pains and twinges from the various beatings he has taken over the course of his long career.

I don't know if you follow any football players at all, but right now Brett Favre is the quintessential achy old pro; he announced his retirement in 2007, saying he was too old and tired to keep playing. Then he changed his mind, went through a huge and rather acrimonious struggle to get back on the roster of his original team and then any team at all, and ended up playing for another 3 years despite "retiring" again in 2008. Despite being old, suffering from injuries both recent and ancient, and no doubt having a stiff back, sore knees, etc., he kept coming back to the game that he knew he should have given up.

(We can only hope he stays properly retired this time.)

As for the "holy rituals of the game" part, that's making reference to the fact that the act of watching the game is surrounded by rituals and habits that we keep doing over and over again, even though we know that they are actually bad for us, much like the game itself is hard on the athletes involved; getting chased and knocked down by 11 aggressive opponents every week (like the achy old pro quarterback did) is worse in scale than gobbling up 2 pounds of chips, cheese, and salsa and a 2-liter bottle of soda while keeping one's buttocks firmly entrenched on the couch for 5 hours, but neither one is going to make you healthier.