In addition to releasing the major OS X 10.11 El Capitan software update for the Mac, Apple has also posted a Safari update for Yosemite and Mavericks users. In addition to improving your privacy, compatibility and security, the Safari 9.0 update for Yosemite and Mavericks systems includes some controls found in the El Capitan edition of Apple's web browser.
These mainly include the ability to mute audio in tabs and additional viewing options in Safari Reader, but not the new Pinned Sites feature.