What exactly is the question? Are you asking if DX9 is outdated now? Or are you asking which is better? Or are you asking if learning DX9 so you can learn DX10 is the right way to go about learning DX10?

If I had to pick whether it's too early to learn DX10 or too late to learn DX9, I'd say it's to early to learn DX10. But the answer to depends on why you want to learn either. In a nutshell, DX9 has more learning material readily available as you've noticed, has much wider accessibility (many more people would be able to run your programs), which also dictates its status in the industry as the dominating API. DX10 is newer, gives access to newer hardware features (geometry shaders.. etc), removes the need to check for hardware support for various features, its programming model is somewhat different from that of DX10 (I don't know exactly how since I only know DX9), but it's vista/7 only. How important any of these differences to you depends on what you want to learn DirectX for. DX9 is not outdated, and I have yet to come across a big DX10-only PC game.

[EDIT]: Personally I find learning from tutorials to be much more faster and effective than learning from books, especially for something like this. See this for example for DX9 learning resources (particularly Evil Steve's tutorials and codesampler.com).

There is not much I can tell you at this stage that isn't already available in the tutorials I liked to in the previous post. Good luck and don't rush things - learn the basics, make simple test applications, get a feel of how things work together, and then try to make something useful with the knowledge. And have fun.