I think my consistent memories date back significantly later than the time when I was nine - possibly 13-15. I do remember some fragments from my earlier childhood, and some of these are quite vivid, visually, but they're just that - fragments. These moments seem to be taken out of context as I can't recall what preceded or followed them, which in turn makes them less meaningful. My later memories are fairly vague too; often all I will remember about a particular period is the "general feeling" of the time, but no specific events, except perhaps a few "snapshots" of things that had seemed especially significant at the moment. Conversations, in particular, are something I'm especially bad with. I may be able to remember what I did at a specific point - at least the most general outline of it - but not what I was saying, or what was being told to me.
It's like watching a vivid impressionistic movie which consists of separate scenes that do not seem to be connected in any more or less coherent manner; before one realizes what is going on, the scene will shift to something seemingly unrelated, and so on ad infinitum. There is no apparent plot or dialogue, only disjointed flashes of feeling and imagery.
This is strange, in a way, because my academic memory is quite good. I easily remember the material I happen to be learning at the time (the more motivation I have, the better, naturally); sometimes I will remember the page numbers or the text precisely as it is on the printed page, so that I can see it again if I close my eyes. I also remember poetry very quickly (it's enough to repeat the poem several times, even when it is quite long, and it just starts flowing on its own).
Sometimes I think that I simply have a well-developed repression mechanism - by preventing me from accessing painful or unpleasant memories, my mind seems to be protecting me from the additional distress they would cause. Besides, I've had a problem with chronic depression for quite a while, so perhaps this has also contributed to my poor memory for events (I've heard quite a number of other people with the same problem complaining of their memories having become worse, and, in particular, of their recollections being "obscure" and not specific enough - one friend described it as having the substance of her memories stolen, even though the memories themselves still seem to be there).