There is no DX9.l that is in XP SP3. As stated above it is only, and read this carefully ONLY, hotfixes in this service pack. DX9.l can be acquired at any time from the DX Runtime site. It will not and is not incorporated into SP3 at all.
Also that info about 9.l being equal to DX10 for XP. I have yet to hear that from the DX team. They have not said anything of that nature on their site or in the private newsgroups.