It really depends on whether your dad was registered as Canadian by your grandfather. If he wasn't registered, it means he didn't have Canadian citizenship at time of your birth. If he was, he would be Canadian however up to age 28. If he failed to retain his citizenship, then he didn't have canadian citizenship at time of your birth. If he did retain his citizenship, only then can you claim canadian citizenship by descent since your father had canadian citizenship at time of your birth. If your father had citizenship but failed to retain his citizenship, he still will not have his citizenship back under the new 2009 law.
Now if your father wasn't registered by your grandfather, he would get his citizenship under the 2009 citizenship law and recognized his citizenship since birth. However the law is not retroactive so you still cannot claim citizenship because the 2009 law says your father is canadian since birth. The important fact you need to know is whether your father has canadian citizenship at the time of your birth.