Ummm, no. Rumple made Hook his lackey by making him do all his dirty work. Having said that, Hook really should’ve known better than to blackmail Rumple.
Actually, I think this is similar to the the hand situation all over again. Rumple does have Hook’s heart and could theoretically kill him at the drop of a hat or puppet him like Cora did to Aurora. However, we have not actually seen Rumple do that to Hook. Hook is CHOOSING to do all these bad deeds for Rumple because he THINKS Rumple is controlling him, much like he thought the hand was acting of its own accord when it was really himself. Rumple has admitted to Hook that he’s going to kill him anyway regardless, so why is Hook doing what Rumple wants when Rumple isn’t literally using his heart to control him therefore Hook could refuse.
Except he’s carrying Hook’s heart around in a bag, patting it, telling him to “sit” whilst having his heart, ect.