I stay in the USA from 2000. Me and my wife were F1 students till 2007. We submitted 1040NR for the years 2000 thro' 2003. From 2004 we started submitting 1040 jointly as allowed per the substantial presence test then. In 2008 my wife became F2. And in 2009 she changed to J1. We submitted 1040 for the years 2004-2008. Can we sumit 1040 for 2009 too or we have to go back to 1040NR again?

File joint return as residents for 2009. On J1 your spouse must pay FICA taxes.

File joint return as residents for 2009. On J1 your spouse must pay FICA taxes.

Thanks MukatA. She did pay FICA. But her employer made her fill an 8233 and they did not withheld any federal tax. Our total fed tax withheld is however enough and we do not need to pay any additional Fed tax. But do we need to take any step to undo the 8233 filed mistakenly?

For future tell the employer that she is resident, so they must withhold FICA taxes and income taxes.
File your tax return as residents.