Unfortunately - your income is taxable in the year it is received and should be reported on your 2009 tax return.
You may not report disability income received in 2009 on previous year tax returns.
As a side effect - 85% of your SS disability benefits will be taxable.
Because your additional tax liability is based on your private insurance carrier mistake - I might suggest to contact them and ask to compensate your additional tax liability.
Let me know if you need any help.