[xorfish]

https://dqydj.com/sp-500-return-calculator/

Average dividend reinvested and inflation adjusted return between 1949 and 2016 is 7.5%

  >>> def comp(A, n, i):
  ...     m = 0
  ...     for x in range(n):
  ...         m += i**x
  ...     return A/m
  ... 
  >>> comp(9000000, 67, 1.0725)
  6053.012676780852

Assuming costs of 0.25%, she needs to invest a little over 6000 2016 USD per year to get 9 million USD.