My dd is an excellent sleeper once she IS asleep - usually goes through from 8pm to 3 or 4 am, then feeds, then up again between six and seven.
BUT - it takes forever to get her to go off - anything from 1 to 2 hours, including after her night feed. We tried everything, including sleeping with her. Nothing worked except giving her my finger to suck, which did send her off a bit more quickly. She cannot keep a dummy in, however.
But we have created an absolute quandary for ourselves, because she has become totally reliant on a finger to suck - and wakes up once I take it away, however soundly she seems to be sleeping. Then the whole process begins again - sometimes this goes on for three hrs, longer than the pre-finger era. I can't sit up most of the night any longer with her.
In desperation, we are considering a form of sleep training: not full-on 'cry it out', but putting her in her cot, with lots of reassurance, but no finger and no picking up to comfort her. Is 9w much too young??