Since One Across is always the first clue in a crossword, 'END' isn't an apt fit. Probably got a bit too cute on that one (if I have to explain a clue, it's probably not a good clue)
"Cha Cha _____" (fixture at many school dances, wedding receptions, bar mitzvahs, quinceañeras, aerobics classes, and probably any open-space event with more than 10 people and a D.J.)
9A
Pop
Down
1D
Subsides
2D
Zero
3D
Phone with the Google Play Store, casually
5D
Pop
6D
Made someone's life really inconvenient on Nov. 1st, say