Humming, 9 months. Concern?

Hi everyone! I have a question for you. I have identical twins that are 9 months old. Recently, my twin b has shown some signs that may be considered neurodivergent and I’d love your opinions as their 9 month pediatric apt isn’t until next week.

The past two days (Christmas) have been rather overstimulating in general, even for myself. Yesterday he was kind of shutting his eyes very hard, almost looking like he was about to sneeze. He did this during dinner - BUT he was eating mashed potato’s that (may?) have contained some black pepper. I thought of that in retrospect. However, family at the table even commented on it and asked if he was okay.

Today during presents with extended family, he was continually humming or making humming noise. He did recently learn “mama” and “mom” this week, and has been saying it often. But this was like mamamammmmm. Just kind of constantly mmmm noise unless he was playing with a toy or occupied. He was tired.

He also shakes his head - but does this primarily when tired. He is about to get his two lower teeth and has been prone to ear infections (he’s had 2 so far)

Am i completely overthinking typical baby behavior? It’s challenging for me because his brother does not do these. I try to tell myself that each baby is different but my gosh is it hard some days!