I believe Galene does[0] Juliusz was working on pion/RTP for it. You can see all the details here [1]
[0] https://github.com/jech/galene
[1] https://github.com/pion/rtp/blob/master/codecs/vp9_packet.go
[0] https://github.com/jech/galene
[1] https://github.com/pion/rtp/blob/master/codecs/vp9_packet.go
* the sender is using a Chromium-like browser (the receiver may be Chromium, Firefox or Safari);
* the codec is either VP8 or VP9;
* there are at least three users in the group.