Is my 8 months old baby suffering from Hirschsprung's disease or severe constipation?

Hi doctor,

I have gotten two different opinions from two pediatricians about my 8 months old boy. One says my boy has Hirschsprung's disease, and the other says it is just constipation. The first doctor did a rectal exam, yielding no explosive stools, and he wants my son to get a barium enema. The second doctor did not do a rectal exam and just felt my boy's stomach, and said it is not hard and has good bowel sounds. She told me to up his apple juice or water to 8 oz per day with probiotics. KUB was done and shows lots of stool in the large intestine, so the doctor told me to give Miralax and liquid suppository.

My son did have suppository a week before the visits with hard poop smear in each diaper ever since. During that time, I had been reporting to my first doctor about my son's constipation. My son started with gentle solids at six months. He is today exactly 8 months old, weighs 21 lbs, and has over 90 % growth in the growth chart. He does not have weight issues. He never had a fever, no blood in stools, has passed his meconium, and had a few projectile vomiting in his lifetime.

My son does not fit the HD diagnosis, but my doctor says because of the rectal exam yielding no explosive stool it means it is stuck in the large GI. Is there harm in performing barium enema? My son already had an x-ray, which shows lots of stool in the large intestine. I also just gave him Pedia-Lax, and he had a good bowel movement for the first time since two weeks. I am attaching a picture. I will give him Miralax this weekend with 8 oz liquid a day with probiotics and no solids for now. Is barium enema an old school method?

I am so torn because the first doctor in a specialist and has 50 years of experience, and he is adamant that my son has HD even after consulting with his colleagues. Could this just be a bad case of constipation? Maybe, I did not insert the first suppository correctly, and maybe my son did not get enough liquid this whole time, this second liquid suppository really helped. The second doctor has eight years experience, and she is so conservative. She does not want to give a rectal exam or even suppository. She says my son is at a low risk and does not have HD. Should I see a gastroenterologist or my son before we proceed with the barium enema or should we just get it done at this point and see the results? I just did not read anything about a barium enema after online research.