What is an amendment

[mcannoles]

can I go back and claim a dependent that has passed away in 2009

[DoninGA · Accepted solution]

No.  You cannot add a dependent that passed away in 2009 on a 2018 tax return.  You cannot amend the 2009 tax return to add a dependent and receive a tax refund since the time to file for a 2009 refund has expired.  You needed to file the 2009 return on or before April 15, 2013 for a tax refund.