C.S.
This happened to our family, too. I think it's fairly common for bedtime routines to get shaken up at 8 or 9 months old. We went with the CIO (cry it out) method and it worked perfectly. The first few nights were very hard. It was so hard for me to hear the cries that I went to a neighbors for 30 to 45 minutes while daddy supervised. We never went back in the room. After 45 minutes or so, the cries would soften and she fell asleep. I remember thining she'd be angry with us the next morning, but she wasn't. By the 3rd or 4th night, she knew what to expect and cried only for 10 minutes or so. After a week, she was able to relax and soothe herself to sleep. We had a Dreamscape on her crib rail (played music, lit up the room) and a silky blanket that she loved until she was 3.
I know CIO is controversial and isn't for everyone. However, it was a perfect solution for us. I think it's easiest to do it before they are a year old because they really get angry when they are 3, 4 or 5 years old and you try to kick them out of your bed.
Good luck, hang in there. I hope you find a plan that works for your family.