Key TakeawaysThe S&P 500 gained 1.1% on Wednesday, Sept. 11, as investors weighed the implications of the latest CPI data and Tuesday evening's presidential debate.Shares of First Solar and other green energy companies soared after energy was a topic of debate among candidates Tuesday.Humana shares tumbled as analysts said Medicare insurers could face pressure in the event of a Democratic presidential victory. Major U.S. equities indexes recovered from early losses to close Wednesday's session higher. The v ...