Múltiples versiones del mismo Python instaladas

He instalado Python3 a través de brew :

brew install python@3.9

Y siguiendo la cadena de enlaces simbólicos de which python3 conduce a:

$ which python3
/usr/local/bin/python3

$ ls -l /usr/local/bin/python3
lrwxr-xr-x  1 user  admin  41 27 Jul 17:44 /usr/local/bin/python3 -> ../Cellar/python@3.9/3.9.13_1/bin/python3

$ ls -l /usr/local/Cellar/python\@3.9/3.9.13_1/bin/python3
lrwxr-xr-x  1 user  staff  55 23 Jul 08:45 /usr/local/Cellar/python@3.9/3.9.13_1/bin/python3 -> ../Frameworks/Python.framework/Versions/3.9/bin/python3

$ ls -l /usr/local/Cellar/python\@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/bin/python3
lrwxr-xr-x  1 user  staff  9 23 Jul 08:44 /usr/local/Cellar/python@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/bin/python3 -> python3.9

$ ls -l /usr/local/Cellar/python\@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/bin/python3.9
-rwxr-xr-x  1 user  staff  13620 23 Jul 08:42 /usr/local/Cellar/python@3.9/3.9.13_1/Frameworks/Python.framework/Versions/3.9/bin/python3.9

También instalé offlineimap con:

python3 -m pip install offlineimap

Y la línea del shebang se muestra:

#!/usr/local/opt/python@3.9/bin/python3.9

que apunta a un binario diferente:

$ ls -l /usr/local/opt/python@3.9/bin/python3.9
lrwxr-xr-x  1 user  staff  57 23 Jul 08:45 /usr/local/opt/python@3.9/bin/python3.9 -> ../Frameworks/Python.framework/Versions/3.9/bin/python3.9

$ ls -l /usr/local/opt/python@3.9/Frameworks/Python.framework/Versions/3.9/bin/python3.9
-rwxr-xr-x  1 user  staff  13620 23 Jul 08:42 /usr/local/opt/python@3.9/Frameworks/Python.framework/Versions/3.9/bin/python3.9

y los dos tienen las mismas versiones:

$ python3 --version
Python 3.9.13
$ /usr/local/opt/python@3.9/bin/python3.9 --version
Python 3.9.13

¿Cómo he podido instalar dos instancias del mismo Python? ¿Cómo puedo desinstalar la versión que no es de cerveza?