It is another phrase for 09/09/2009, the official Cirno day. It is based on a very popular Japanese internet meme.
Simply 9-9. September 9.
9
57 i think (may 9) 57 i think (may 9) 57 i think (may 9) 57 i think (may 9) 57 i think (may 9) 57 i think (may 9) 57 i think (may 9)
9 squares in tic-tac-toe
He was 8 to 9 years old.
1152
yes 9+ 9 9 9 9 + 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 +
2.250388e+167
90
It's 9*9*9*9*9*9*9*9*9 or 387,420,489
9 + (9/9) = 10 (99/9) - (9/9) = 10 [ (9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9) / 9 ] + (9/9) = 10
9+9+9+9+9+9+9=63
9 + 9 + 9 + 9 + 9 + 9 = 54
9 nine 9 9 9 9 9 9 9 9 9
9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 - 5678 = -5606
4782969
99 = 9*9*9*9*9*9*9*9*9 (nine lots of 9) = 387,420,489