There are no settings with in the TE client to take advantage of the vibration on the 9100's..
I'm not sure if the MC9190s even have a vibrating motor built in. If they do, and Motorola provides access to it via their EMDK, you could in theory write a very small application that simply buzzes the motor when run. You then could use the RunApplication TelnetCE scripting method to call that application every time a condition is met. You could setup a simple scan handler that would take the scan data in, vibrate the device by calling your custom application, and then immediately just pass the scan data right through.
Activate( On_Input, strScan, intScanType ) //Activate on Scan
RunApplication(YourVibratingApp.exe) //Call your application
ScanString(strScan) //Pass ScanData as Scan
You could even add custom processing into the ScanHandler so that it vibrates only for specific symbology types, or for specific qualities of the given barcode scan.