9 hours is not too long, they usually have high, low and warm settings, some have 'auto' which cooks on high for a set number of hours then switches to low.
I have two, one full size, one small one.
Lamb is fabulous in the slow cooker, just put a joint in with nothing and leave it, the fat melts and bastes the lamb.
They are all slightly different so you will need to use a bit of trial and error.
If you are using a recipe for an oven baked casserole or stew on a hob then reduce the liquid to 1/3 of what you would have used.
I make steak and kidney pudding in mine, you make the pudding in a Pyrex bowl, add boiling water tot he pudding, then put abut 3 inches of water in the sc and put the bowl in there.