Do you have any compelling reason not to just move your window? And/or adjust the time you take your meds?
I also prefer a “later” eating window (psychologically, if I eat in the morning, my body just expects food all dang day) so I understand not moving it to 9am. But, could you maybe eventually get to a place where your eating window is 1 - 3 or 2 - 4 and take your meds then?
what do you mean ineffective? whether you eat or not should have no impact on whether your adhd meds are absorbed afaik. i’d talk with your doctor or pharmacist about it because that sounds odd.
personally i just feel ill and shaky if i take concerta to an empty stomach but it definitely works on an empty stomach too, it’s not a drug that requires fats or anything else to dissolve, it’s a water soluble drug.