English to Japanese Bus/Financial Finance (general)

以下に３箇所出てきます。行使可能になるということかと思うのですが、どんな訳が使われていますか？

our stock options become exercisable (“vested”) for 25% of the shares in each year, measured from September 2０, 2006. Therefore, none of your FY07 option award can be exercised before September 2０, 2007, and all of your FY07 option award will be fully vested on September 2０, 2010. You can exercise your stock options for any shares that have become vested.