Theme hint:  Even without the title, the clues to the long answers tell us that we’re looking for some well known people’s names to show up in the puzzle.  But don’t ignore the “Hits” part of the title.   Once you get one, you’ll quickly see what holds the puzzle together.  Keep in mind that the clue is literally true, but the answer will be something that’ll probably be pretty familiar.  It helps to be a little older to do this puzzle, ’cause most of the theme references are from “back in the day.”

Specific clue hints:

53-Down.  Kind of cat:  There’s just no end to this one!

90-Across.  Classical “You too?”:  The guy saying this wasn’t just complaining about a minor problem.

71-Down.  Botanist’s microscopic study:  2 words; not fancy scientific words

9-Down.  Cuffed:  Not as in handcuffs; bible-language, not ordinary speech

68-Down Egg choice: Think big

83-Across Barbecue needs:  The clue should really have a “perhaps” at the end, ’cause a lot of folks bbq without these

54-Down Away for a while:  e.g. from the army or from a job

15.Down Bread flavorer:  Think of after the bread is cooked rather than before

39-Down Cause of yawning:  Or of existential angst

75-Down Cutthroat:  3 equal length words