Finally! Adobe released a 64 bit version of the PDF iFilter. You can get it here: https://www.adobe.com/support/downloads/detail.jsp?ftpID=4025.

But before you decide if this is the iFilter you wanna go with. Check out Je Li’s performance measurements comparing Adobes and Foxit’s iFilter: https://blogs.msdn.com/opal/archive/2008/12/10/pdf-ifilter-battle-foxit-vs-adobe-64bit-version.aspx