Both Android developer and Chrome OS developer sites have sections to support stylus for Android app. Those sections even mentioned Wacom. All the basics to build a stylus-aware Android app can be found at those official sites.
The link below guides you through the Android app development process, step by step:
Overview – Information on the Android API
Basics – Details on tablet specific Android API
Reference – Links to the complete Android API packages and classes
FAQs – Useful Android programming tips
Sample Code – Full Android API demo sample