I use AR 9.2.0 on XP and all Apple docs PDFs (embedded MyriadSet, default Apple font) render very badly.
Some glyphs would be off by 1px, e.g. attached shot from CocoaFundamentals.pdf at 100%.
It seem to depend on zoom and can go away or get much worse than the shot. None of rendering options combos can fix it.
PS: If that's part of a known bug, disregard this.
The problem could lie in the way the pdf files were created. I doubt it is a Reader issue unless you can demonstrate that the problem doesn't occur with other versions of Adobe Reader. If the problem lies with the document, then you need to contact Apple not Adobe.