It would be better to ask this in the Acrobat forums.
To answer TonUden's question directly, it depends upon what your client means by certified PDF!
There is no such concept in terms of the PDF specification or any ISO PDF standards. A provider of Acrobat plug-ins, Enfocus, provided the concept of certified PDF with one of their products a number of years ago and the Ghent Workgroup (an industry trade association in which both Adobe and Enfocus participate) provided a further specification of this.
In reality, though, so-called certified PDF is nothing more than a digital signature on a PDF/X file that indicates that a preflight operation was run on the file and it passed that test. That doesn't necessarily mean very much in terms of how well the file will print or if it will print at all!
As Dov says, it's very likely that what they actually mean is a PDF/X file - some flavors of which you can make from InDesign using the Export > PDF (Print) dialog presets, and some you can make using Acrobat Pro.
However it's very important to find out exactly what they want:
- There a couple of versions of PDF/X (the older PDF/X-1a is very widely supported but can only cope with CMYK - the newer PDF/X-4 is more flexible and handles things like spot colors, but is often not printable on older hardware).
- When exporting to CMYK you have to choose a color profile - and that will depend on the printer's hardware and proofing systems. You may have to choose exactly the right one, or they may be able to convert back from any profile - until you find out you're working in the dark.
- Of course you also need to know the printer's rules about bleed, TAC, etc.