Weller is quite correct. The FBAR form does NOT affect your tax due, and the IRS isn't looking for ways to play 'gotcha'.
I know for a fact that a FBAR form I filed a few years ago arrived late. And I was in the USA, and no one came to get me, or wrote to me to appear and explain myself. Now for the Facebook guy who just renounced citizenship before the public float to save $600M....well......he would have been a big target for the IRS. You and I who just try to comply are not really on the radar screens.
File the form for 2009 if you need to, but at the end of the day, even the IRS have no real means at present of pouring over daily balance statements to find the possible one and only time that your combined accounts might have hit the magic $10K threshold. I personally would file, with a cover letter explaining why it wasn't filed when due. That 'income' was a one-off, and when you go back to look at your balances, you still might not be over the $10K.
For this year, do your best.....it's really just a form. Don't 'awfulize' and don't worry. You likely will NOT be dragged from your bed by agents of the evil IRS and put on a plane to Ft. Leavenworth.