Adobe reader 10 is next version of adobe reader 9. You can get more features and security in adobe reader 10 as compare to adobe reader 9.
You can adobe reader 10 free download from here and adobe website. But remember in adobe reader free version you will never get full functions for PDF files.
In Adobe Reader 10 free download you can just open, read and print pdf files if you are going to create a new pdf file or want to modify pdf files then you must need to download adobe acrobat reader 10 or acrobat reader x.
We will never recommend you free download adobe reader.