Is ES9 the latest version of JavaScript?

Answer 1

No it's just ECMAScript now, we don't have version numbers anymore, instead we have a living standard (like in HTML).
New features go through testing, they start at stage 0 and once they are stage 4 they are part of the ECMAScript living standard.

Answer 2

Hey, if you are wondering, here is the latest update of ECMAScript (ES2020) :
https://www.sololearn.com/post/387031/?ref=app

Answer 3

You can check which featues are finished, or in the works, here: https://github.com/tc39/proposals/blob/master/README.md
You can check how browser support is for any feature here: https://caniuse.com
For example, support for BigInt could be better, support for globalThis is already pretty good.
The ECMAScript 2021 snapshot is here but again it's best to not think in version numbers:
https://tc39.es/ecma262/
New features will be supported by all browsers eventually (unless you use Internet Explorer, it is no longer developed).
If you need full browser support right now, or backwards compatibility with Internet Explorer, check out https://babeljs.io/ which can automatically compile new js features (even stage 0) to javascript code compatible with old browsers.

Answer 4

Is ES2020 supported by every browser