Yes I am using in terminal.
Here is the process that I used:
Install pyenv using homebrew.
brew update
brew install pyenv

After the installation, you need to set up bash environment. Since macOS uses zsh, you need to update .zshrc and .zprofile files as suggested in the GitHub page:
echo 'eval "$(pyenv init --path)"' >> ~/.zprofile
echo 'eval "$(pyenv init -)"' >> ~/.zshrc

Now, you can install any version python using pyenv:
pyenv install 3.9.9

And after that, set as global.
I usually setup virtual environment but it is your choice.
Hope this can help you.