The full form of VP9 is last VPx-based codec

VP9 is a video codec technology developed by Google. VP9 is an open-source technology and is free from royalty fees. The VP9 codec is mostly used for streaming videos over the Internet and claims to reduce the bit rate of video transmissions by 50% while maintaining a high quality. The VP9 codec, which is an improvement over the VP8 codec and was previously named “NGOV” (Next Generation Open Video), is supported by both the Chrome browser and YouTube. It is a native format in HTML5 and works with Opus audio and Ogg Vorbis codecs.

VP9 is an open and royalty-free video coding format developed by Google.

VP9 is the successor to VP8 and competes mainly with MPEG’s High Efficiency Video Coding (HEVC/H.265). At first, VP9 was mainly used on Google’s video platform YouTube. The emergence of the Alliance for Open Media, and its support for the ongoing development of the successor AV1, of which Google is a part, led to growing interest in the format.

In contrast to HEVC, VP9 support is common among modern web browsers (see HTML5 video § Browser support). Android has supported VP9 since version 4.4 KitKat,while iOS/iPadOS added support for VP9 in iOS/iPadOS 14.

Parts of the format are covered by patents held by Google. The company grants free usage of its own related patents based on reciprocity, i.e. as long as the user does not engage in patent litigations.

see also What does VP8 mean? What is the full form of VP8?