OWC 6GB (2GB + 4GB) PC8500 DDR3 1066MHz SO-DIMMs Memory Compatible with Late 2008, Early 2009, Early 2010 MacBook, MacBook Pro Unibody Models, 2009/2010 Mac Mini, 2009 iMac Models at Amazon.com
My 2009 Macbook Unibody still running hot in 2020 with a new SSD and maxed out RAM : r/mac
MacBook (13-inch, Late 2009) - Technical Specifications
13-inch MacBook Pro Mid 2009 Memory Installation Video - YouTube
Amazon.com: OWC 16GB (2 X 8GB) DDR3 1333MHz 240-pin DIMM ECC Memory Compatible with Mac Pro 2009-2012 'Nehalem' & 'Westmere' Models (OWC1333D3W8M16K) : Everything Else
Timetec 8GB Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 for Mac Book (Mid 2010 13-inch), Mac Book Pro (Mid 2010 13-inch), iMac (Late 2009 27-inch), Mac Mini (Mid 2010) SODIMM MAC
Late 2009 MacBook ram compatibility | MacRumors Forums