First of all, the regulator should not allow the battery to rise to anywhere near 9v, something just over 7v is OK, so the regulator is definitely duff. It sounds like your ammeter is also duff as it is allowing current through but not showing a reading. I'd change the regulator first as, at present, it is cooking your battery. After fitting a new regulator (or fixing the old one but probably not worth investing too much time in it) see how the ammeter looks. Unless it has miraculously woken up it is likely you'll have to change that as well.