I am very sorry to hear of your loss.
Concerning your tax return for 2009, you will still be able to file your return as married and file jointly with your wife. This will be the last year that you can do that, unless of course you were to remarry.
Across the top of your Form 1040 tax return, you should write "Deceased", and then write your wife's name and date of death. You should sign the return and behind your signature write "Filing as Surviving Spouse".
Everything else will remain the same as in previous years. You will report any income that the two of you had during the year and any deductions to which you are entitled. This will be the last year that you need to file a return on your wife's behalf.
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Thank you john