Reasonable adjustments at Pre-School/Nursery

Hello, I'm wondering if anyone can help me. I'm an autistic mum to two boys; my eldest has an autism diagnosis and my youngest is awaiting assessment. I have a question about reasonable adjustments surrounding drop off and collection times at nursery/ preschool.  My eldest son has a later drop off time at his school so he doesn't have to walk through the crowded playground, this is part of his reasonable adjustments, however I've asked my youngests preschool setting if we can arrive at five to 9 (earlier)  to avoid the main rush and settle him in for 9am, however they have refused this based on the funded place starting at 9am and that they have no responsibility to do so. At the moment, I have to drop of my son later at 9:15 to accommodate this, however I can't help thinking it is quite unfair to refuse given I'm only asking for this time to settle him in. Is this the case everywhere and am I wrong for seeing this as somewhat arbitrary? 

Thank you in advance