If you have to leave the dog when it's young, it should be just fine if you leave it in a room with plenty of toys. Unsupervised, with the run of the yard or the house, is a recipe for trouble. So...don't worry! You can handle it!
"Loyal and obedient, Australian Shepherds will follow their pack leader (that's you!) to the end of the earth. They are highly skilled at herding and agility games. Unlike the Border Collie, the Australian Shepard has an 'Off Switch." Which means that they are just as happy to lay at your feet, as they are to play ball or any other 'job' you choose for them."
http://www.doodlesvilleva.com/aussiedoodle-info.php