If you were not scheduled over 8 hrs originally, you can go over 8 hours with no legal problem and no violation of the contract, as long as you don't depart an airport having already exceeded 8 hours and you get a legal [at least 16 hours] rest period after you land at your layover station or home base. It is in Section 12.C.2.c.i
"A pilot who, due to headwinds, ATC delays or other unavoidable circumstances (including an intermediate stop for these reasons) is projected to exceed 8 ABH without an intervening legal rest period, shall be permitted to continue to base or to his layover station, whichever is scheduled to occur first, at which point he shall receive a legal rest period. However, a crew shall not block-out from a location after having exceeded 8 hours of block time in a 24 hour period without a legal rest period." (referenced in red as No. 1 above)
So I have to disagree with Fedupbusdriver, it's legal and in the contract to make you continue to your destination, as long as you have not already exceeded the 8 in 24. Your only recourse is to call fatigue.