Hi Sarah,
That’s a mighty weird issue you have there. That sounds very specific to the hardware or its drivers. A quick search didn’t turn up any drivers for this tablet from AipTek, so that wouldn’t be it. Did you install any software for the tablet?
Does the installation of the tablet also affect keyboard behaviour in other software? Does the strange behaviour disappear if you remove the tablet? One thing worth checking is your keyboard language system setting. Some software is very sensitive to that (not sure about PT9) and will only work correctly with the US keyboard setting. Some control devices change that setting when installed, so that might be it.
If this little troubleshoot gets you nowhere, I suggest you come over to the PT9 Mac forum on https://duc.avid.com/ an inquire there. There are more users, so a better chance that someone will have encountered that specific hardware.
IHTH,
JC Boulay
Technical Director
Audio Z
Montreal, Canada
http://www.audioz.com