It is stated that Jesse is in kindergarten which would make him around 5-6-years-old. But Superman had only been in the public eye for 3 years at that point. While it's true he could have fathered a child before he was a public figure the photo LeAnn shows as proof she had a relationship with Superman he is in his full costume which his mom made for him only 3 years earlier. LeAnn also states her pet name for him was Super but he also didn't go by the name Superman until Lois named him.
When the president arrives and the loud noise is played, Clark and Jesse are watching on TV and both react to the noise. LeAnn says she can't hear any loud noise but if it's true that only Clark and Jesse can hear it with their super-hearing then the other people around the president shouldn't have been able to hear it either. Since it's obvious that all the people around the president were affected by the loud noise then LeAnn and Lois should have heard it too.