No you cannot.
Charge it with a 12 volt battery charger.
No, a 12 volt charger will overcharge a 8 volt battery and destroy it.
A 12 volt battery charger is designed to charge 12 volt batteries.The answer to the Related Question explains how any battery charger works.
No, the battery charger has to match the voltage of the battery it is to charge.
If you are asking the question, can you charge a 6 volt battery with a 12 volt charger, the answer is no.
No.
no it can't
No it will not work
No
NoNo
No, an automobile battery charger outputs 12 Volts. This is far too many volts to charge a 5 Volt battery. You would destroy the 5 Volt battery with this charger.
no, if you charge 9 volt battery with 12 volt battery you will destroy 9 volt battery