Its not really that the 9 amp hour is running the other electrics, more your alternator is running the electrics. The battery acts as a cushion/storage system, heavy draw on a battery is normally when everything is working at once and your alternator can't cope, IE when pulling up at a junction at night, lights on, indicators on, brake light on, but this is only at small times.
I don't have indicators on my 500/4 so can't comment on their effectiveness with the 9 AH