First of all we should specify which "equivalence relation". Since not specified, I assume based on Myhill-Nerode relation.
Totally 8 equivalent classes- the last one for a dead set of strings (can never be in language after appending any string). So, the min-DFA for $L$ will have 8 states with one being a dead state.
7 states + 1 dead state which I missed. $\Rightarrow$ 8 classes . You can verify with partioning method.