R.-
Sorry you are having such a hard time with this baby. I can totally relate, my first and only child still wakes a number of times every night to nurse or be comforted back to sleep. We also co-sleep and the amount of wakings varies depending on what is going on with her (teething, tummy ache, etc.) On a good night she may only briefly wake once or twice, on a bad night it can be every hour! It has been like this since day one and she is now 23 months old. I know that she wont be like this forever, and your baby wont either, but I would bet it's harder for you to deal with the sleep deprivation with 9 other kids to care for!
I disagree with others who say CIO is not cruel, babies do not understand why their moms are no longer tending to their needs and letting them cry by themselves. It sounds like your instinct is telling you that it's not right, but you are desperate right now and sleep deprived. Here are some other ideas:
Have you looked into a food sensitivity or intollerance? Does she seem fussier than normal?
Do you wear her in a sling during the day?
Does she take decent naps?
Is she teething? I definitely would try some motrin or tylenol before bed and see if that helps. Personally, between 8-9 months was the worst time for my daughter when it came to sleep and I think it is because there are a lot of developmental things going on too, they are working on new physical and mental tasks as well as teething.
She sounds like a high needs baby, have you ever read about high needs babies on Dr. Sears website? He may have some more helpful tips for you as well.
www.askdrsears.com
Have you also thought about possible allergens in the room? Does she have comfy pajamas?
I'm sure most of this has crossed your mind, but I really think given your babies temperment from what you have said, that co-sleeping is the best thing for both of you. I think making her sleep by herself and trying CIO right now will only lead to more sleep deprivation and probably many tears from both of you. You may also notice more changes in her during the day if you stop meeting her night time needs (clinginess, withdrawing, anger, anxiety, etc.)
I really feel for you though and suggest that on the nights that your husband is home that he help with some of the night time feedings so you can get a little more sleep. Please check out any medical causes that might be related to the night waking. Good luck!