Unfortunately, AIN values are returned only in millivolts. There is no way to set up percentage values according to AIN value in the device configuration. However, Such conversion should be rather simple to do on the server side if you are using your own platform.
The closest thing you can achieve by only using device configuration would be configuring AIN1 IO element to |Priority - High|Low level - 3000|High level - 9000|Operand - On both|SMS text - "AIN Value: %io50180"|. This way you will receive SMS messages, with current AIN1 value in mV, when AIN1 crosses 3000 or 9000 thresholds.