Worth buying latest OBD2 for old Kangoo to monitor voltage level?

I am interested in having an OBD2 scanner to monitor the real-time system voltage level, because my battery goes flat quite often and I am wondering why. Before buying one, I have two questions:

Can anyone advise if I can get the real-time system voltage of my Kangoo with an OBD2 scanner? I saw a guy monitoring the voltage with a BlueDriver in his YouTube video. I checked...

Worth buying latest OBD2 for old Kangoo to monitor voltage level?