It is the developement of deuterostomes because the animals that are deuterostomes are including those of the phyla Echinodermata (e.g., starfish, sea urchins), Chordata (e.g., sea squirts, lancelets, and vertebrates), Chaetognatha (e.g., arrowworms), and Brachiopoda (e.g., lamp shells). This includes vertebrates, so yes that’s how sharks and starfish are related.
