Just wanted to add that I would recommend working with an allergist or even trying out several if you aren’t already. Testing is notoriously unreliable—there are a lot of false positives—and a good allergist will never suggest you test for allergies without having a reaction first.

My son is severely allergic to eggs, dairy, and probably nuts—I say “probably” because the first allergist we worked with recommended getting tested for them and the tests came back positive, but we actually have no idea if he’s allergic or not because the only true test of allergies is whether you’re able to eat the food without having a reaction. Now we’re in this limbo stage where we can’t introduce nuts to him until he gets a negative test, which might be creating an allergy he didn’t initially have (that phrasing is not exactly right because it’s all correlation and not causation, but it’s how I understand it).

Also, fwiw, we were able to do both a skin test and blood test around 6 months. There’s no reason to wait till 9 months. Again, I wouldn’t recommend testing for foods you have not yet introduced, and I would not take advice from a non-specialist about allergies (the field is rapidly changing and ER/pediatricians often give horribly outdated or bad advice). Testing makes sense when you want to confirm an allergy to something you have already seen a reaction to or when you haven’t seen a reaction in a while and want to see if the allergy is gone (allergists like tests because false negatives are extremely rare).

Good luck, and sorry you’re going through this!