The answer to your question is 'Yes". Foods with a glycemic index of less than 50 are considered safe for diabetics.Compared to table sugar (glycemic index of 80) stevia (Stevia rebaudiana) has an index of 0. Please also take a look at the following RG links.
Article Safety and efficacy of health supplement (Stevia rebaudiana)
Article Stevia Derivative and its Potential Uses in Diabetic-Directe...
Article STEVIA AN UNTOUCHED NATURE’S GIFT CAN BE A BOON TO DIABETIC
Article Natural sweeteners: Health benefits of stevia