Can I be charged with a DUI if I've only had one drink?

I was driving home from the bar last night on cinco de mayo but I had one drink (literally) because I knew I had to drive home. I was in a part of town that I didn't know so when I was trying to find my way back I made a funny turn and my lights weren't on yet, my automatic lights didn't turn on but it was so well lit I didn't realize until after I saw the cop behind me. By that time he turned his lights on and pulled me over. I placed my keys on the dash and I told him right when came to the window everything I previously stated and he asked me for license and Reg and if I had been drinking and I told him one drink, he asked for time frames and where I was coming from etc. I was asked to come out of the vehicle and I took their field sobriety tests and ended up blowing a 0.09. He then gave me a lecture about how I have my whole life in front of me and to take what he says to heart. They then gave my back my license and registration and let me back into my car and I drove away after 20 minutes. I will prefix this with that I understand drinking and driving is bad and I have never done it before. I have a family of alcoholics and I understand the entire spectrum of negative impacts it can have on my life. What I am curious to know is if I can be cited with a DUI after the fact and if I will be charged with anything even though he let me go. Also if anyone knows where the reports they file about the experience go to.