Answer
The following is a list of font related export fixes since 9.0 SP2.
Fixed in 9.0 SP3
CQ00255440: ArcMap crashes on batch export of Kanji text to .PDF. This was due to a GDI leak when font embedding is on.
Fixed in 9.1 Final
CQ00257246: Wingdings and other symbol encoded fonts in a text element embedding in .PDF cause errors when opening in Adobe Acrobat.
CQ00257356: Text elements referring to missing font break embedding in .PDF, .EPS, and .SVG when the missing font is one of the Standard 14 PostScript Fonts (Times, Helvetica, etc.), ArcMap displays the text with its TrueType equivalent (Times New Roman, Arial, etc.). When the map is exported with font embedding turned on, the embedding gets messed up and many characters in the text element using the TrueType equivalent do not display.
CQ00251119: .PDF, .EPS, and .AI export do not correctly support Type1 OTF (OpenType) fonts the vector exporters do not encode the correct face name when exporting maps that use OpenType (OTF) fonts with Type1 information inside.
CQ00250742: Inserted .EMF images report font names incorrectly, creating font problems in the PostScript export formats of .AI, .PDF and .EPS. Italic fonts coming from an inserted .EMF image don't flag the Italic true/false correctly, so font names in the ArcMap exporters are figured incorrectly.
Fixed in 9.1 SP1
CQ00272563: Italics are lost when exporting to .PDF with Garamond font set to Bold and Italic. Using fake italic or fake bold text together with normal text corrupts .PDF, .EPS, and .AI export. When creating two text elements, one in italic or bold and the other normal, and they are the same font, and that font does not have a bold or italic version installed, the exported .PDF, .EPS, or .AI document will be corrupted. ArcMap is not correctly doing the fake bold or fake italic in these cases. The problem occurs with font embedding both on and off. SVG is ok. In Illustrator, opening the document returns an 'offending operator Tf' error. In Acrobat, opening the .PDF returns a 'Could not find font in resource dictionary, using Helvetica instead' error.
CQ00265743: Map export to .PDF and .EPS formats with font embedding turned on can create corrupt export files when the map contains certain fonts, such as Tahoma or other system fonts.
CQ00253910: Some characters in symbol fonts, such as Webdings or Wingdings, may display the incorrect glyph when exported to .PDF or .EPS formats.