Serving Rule

Yesterday I had my opponent do start his serve in a way that looks like fault to me. Don’t have any video right now. Here’s what he does. Context: I know BWF rule 9.1.2 “on completion of backward movement….” He directly begin his serve stance by pointing backward (think of it like a slingshot aiming) Of course he then takes few seconds to initiate the forward movement. That pause is what i’m wondering if it’s a fault?