Direct deposit was made to my bank account in error by the company from 2009 to 20014 do I need to pay back in full ?

Yes, you need to pay these funds back.

If you received funds from your employer, and it was an overpayment, you will be required to repay the money to the company. You can attempt to negotiate the payment amount, work out a payment plan, or pay it in full. However, the money wasn't earned by you, and belongs to the company. Good luck!

If you received money you did not lawfully earn, you have no legal right to keep it. Yes, of course, it needs to be returned.

See if you can negotiate allotments but you will have to pay back. On the other hand, amended tax forms to capture the loss of revenue for those years so the taxes are less and you get credit.

I agree with the cacophony of answers that advise that if you got the money and you were not entitled to it, the law does not let you simply keep the windfall created by the mistake of another. That said, my answer to you from a technical legal standpoint cautions that depending on whether or not the employer has filed a lawsuit against you or not at this point, some of the money it seeks may be outside the statute of limitations, meaning the employer may have waited too long to reach all the way back to 2009 to get the money. The nature of the payment will decide what cause of action can be used to seek the money, but I think it is unlikely the employer can reach back 6 years to get all of the money. It is important that you seek the advice of an attorney on this before you take any positions. You do not want to do anything in communicating with the employer that would be considered a reaffirmation of the debt. Good luck to you.