Scorpion deadliness can be determined by the size of the pincers and the tail. Small pincers and a large tail usually indicate that it use a more potent venom to attack and kill its prey. Larger pincers and a small tail usually indicate the opposite, it relies more on its pincers than the venom in its tail.
As stated, we do not really have anything too venomous in Aus (makes a change from some of the other creatures here
) although you may get a bit sickly for a few days. Kids can be effected much more although it would be very rare for it to be fatal.
Catch it in a jar and move it outside away from the house if you are concerned, no need to kill it.