Is there any way to access all plugins hosted on jQuery website and their information using an API?
Not yet. See #3 and #51 where we asked for proposals and nobody provided any. This will come in time, but it will come faster if someone actually provides details about what they're looking for :-)
For start why not just generate all the plugin manifests in a public directory?
For example under plugins.jquery.com/manifests have a directory with all manifest files of all the plugins listed on your website.
Plus a file with a UNIX timestamp of the latest plugin addition would be helpful.
Anyone will be able to access the directory and parse each one by himself.
It will be a viable option, at least until a real API will be proposed and created.