Ok. @Arjun Sir.
@Prajwal Shift-Reduce Conflict (NOT AMBIGUITY)will solve by yacc by preferring Shift operation over reduce operation.
So, here though it will find 3∗2 (E∗E) handle on top of the stack initially, it will shift on reading + instead of reducing with E→E∗E.
so it work like right associativity(and we know priority is same due to ambiguous grammar.)
so 3*(2+1) =9