I went to two different doctors for pregnancy and was told two different due dates july12 and july17 is it possible to have conceived in september ?

Very unlikely: Normal pregnancy is 40 weeks so count backwards that amount of time or use any of various online calculators. For instance, http://www.Baby2see.Com/conception_calculator.Html says date of conception somewhere btwn 15th & 28th of october, so it's very unlikely that you conceived in september. Btw, due date of july 12th & 17th, is essentially identical, assuming based on early ultrasound or lmp.