ADDED after your details and I'll edit out my first reply since it needed the details....
Thanks for filling us in! You're right to be frustrated!
First, work with your own daughter when there's no play date happening. Is she a kid who doesn't like to clean up her messes, period, even when another kid wasn't involved? If so, that needs work -- I'd even make play dates contingent on her working with you to clean up beforehand and being crystal clear with her that you WILL inspect before her friend leaves later, and if daughter refuses to clean up there will be a real consequence. Sit her down and have a firm talk about why she is risking never having a friend over again. If they are pulling out drawers, going into the bathroom to play, etc., they lack boundaries and occupation. Be sure she understands what specific actions will end play dates for a long time to come AND get her a consequence (something taken away for a certain amount of time) if she and her friend do those actions.
And be sure to:
One, have specific things available for the girls to do. You don't have to order them around, but should have some things around like craft kits that are easy to do, pens and paper, outdoor toys, whatever. If things get crazy, do not hesitate to direct them to what is available and say "You can choose to do X or Y right now" -- it breaks the pattern of randomly tearing up a room and "exploring" in your stuff. Some moms will say "Oh, no, that's micromanaging" but at eight, some kids are still not great at sustaining play or at deciding what to do if there are two of them. It beats the heck out of letting them figure out what to do and ending up with a nightmare of mess.
Two, start winding down the play date 30 minutes before pickup--you get the girls, assess any messes and tell them while you stand there that "It's time to clean up now because Susie's mom is coming in 20 minutes." Stand there and chat with them as all three of you pick up but ensure they do the most. Don't tell them "clean up" and leave them at is too huge an order and they will be overwhelmed and not do it...though they will be less overwhelmed if you've been checking in frequently to ensure they are not making a huge mess for hours.
Three, ensure they can't sneak food. Tell them at the start of the play date that you will happily provide a delicious snack later (about halfway through is good) and put all other food out of their reach long before the playdate. Tell your daughter before the play date that if they sneak any food, there will be no snack for her or her friend, and she, not you, will have to tell her friend why. If they whine, don't cave. Frankly I'd ensure my kids didn't have free and open access to snack foods at any time until they were old enough to know to ask, or to be trusted to not make a mess.
A big part of this is your daughter and the fact that when another kid's around she loses whatever respect she shows for the house and the stuff in it. Tell her that, and tell her that her next play date will determine whether she has others. Also-if kids run and hide when the parent who is picking them up arrives, the parent doing the picking up can clearly say, if you don't come out now, you will lose X.
I've heard a parent whose kid was hiding with his host at pickup, call to her kid that "If you don't come now, we are not going out to dinner from here like we planned. You have until the count of 10." That kid scooted out pretty fast. But he also knew mom would DO it -- she would really haul him home and be very clear that his own actions meant he lost a dinner out that he wanted to have, even though it cost her dinner out too.
Play dates can be terrific for your kid and for you. They let you get to know your child's friends better which is wonderful (and helpful--we need to know our kids' friends!). They also teach your child how to be a host and how to be a guest. Your daughter will do better on play dates as she gets older, but for now, it sounds like more direction and monitoring and suggestion is needed for her play dates, as well as before the play dates, so your child understands that there are no play dates without HER being responsible for what happens and for the condtion of the house afterward.