Well, though I am sure you would appreciate it if there were more time between September 5 and 16, it sounds like Mr. September 5 was too early. When you said "September lmp 2," do you mean the first day of your last period was on September 2? If so, presumably you were still bleeding on September 5? It sounds like you didn't have an egg at that time for Mr. September 5 to fertilize, and his sperm would not have lasted 11 days in your body.
Hi, did you get your due date from the doctor doing an ultrasound? If so, how early in the pregnancy was that?
According to the online pregnancy calculator, if you're due June 9, you conceived around September 16.