homebrewでpython3.9のインストールでエラーが起きる

前提

その前にも同様のエラーがおき、brew postinstall python@3.9をしろと言われたのでしたのですが、また同じエラーが起きてしまい使えなくて困っています。
PATHを通そうとしても使えず、python3.8が代わりに出てきます。
どうか解決方法を教えて下さい。

発生している問題・エラーメッセージ

==> Postinstalling python@3.9 ==> /usr/local/Cellar/python@3.9/3.9.13_1/bin/python3 -m ensurepip ==> /usr/local/Cellar/python@3.9/3.9.13_1/bin/python3 -m pip install -v --no-deps --no-index --upgrade --isolated --target=/usr/local/lib/python3.9/site-packages /usr/local/Cel Last 15 lines from /Users/matsuochinyu/Library/Logs/Homebrew/python@3.9/post_install.02.python3: File "/Users/matsuochinyu/Library/Python/3.9/lib/python/site-packages/pip/_internal/cli/req_command.py", line 205, in wrapper return func(self, options, args) File "/Users/matsuochinyu/Library/Python/3.9/lib/python/site-packages/pip/_internal/commands/install.py", line 466, in run self._handle_target_dir( File "/Users/matsuochinyu/Library/Python/3.9/lib/python/site-packages/pip/_internal/commands/install.py", line 521, in _handle_target_dir shutil.rmtree(target_item_dir) File "/usr/local/Cellar/python@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/shutil.py", line 734, in rmtree _rmtree_safe_fd(fd, path, onerror) File "/usr/local/Cellar/python@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/shutil.py", line 667, in _rmtree_safe_fd _rmtree_safe_fd(dirfd, fullname, onerror) File "/usr/local/Cellar/python@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/shutil.py", line 690, in _rmtree_safe_fd onerror(os.unlink, fullname, sys.exc_info()) File "/usr/local/Cellar/python@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/lib/python3.9/shutil.py", line 688, in _rmtree_safe_fd os.unlink(entry.name, dir_fd=topfd) PermissionError: [Errno 13] Permission denied: 'configuration.py' Warning: The post-install step did not complete successfully You can try again using: brew postinstall python@3.9

補足情報（FW/ツールのバージョンなど）

MacOS:catalina 10.15.7