It doesn't really matter even if there are, in the case of hardware implementations -- because hardware decoders/encoders are typically fixed-function hardware blocks with fixed functionality. They are not designed for flexibility or reuse between formats. They are designed for exactly 1 function and nothing else.

Even if AV1 and VP9 share structurally similar components, no VP9 decoder is going to work out of the box. It may mean that people who produce AV1-capable encoding/decoding hardware have a better starting point, though (provided they had VP9 hardware, beforehand)