I have no idea what to do to export it to a pdf. Does anyone have an idea?
First, update InDesign to the latest patch for Version 9 or install CC (2014) (version 10) and update that.
If that doesn't solve the problem, put the whole crash report on Pastebin.com and give us a link to it.
Also, see Adobe Community: File Crashing on Output - printing/PDF/other
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