Supporting 4 year old with ASD

We have a 4 year old who has been diagnosed with ASD. He has a medical diagnosis as well as an IEP from OUSD. He will be in an inclusion program, with support (his issues are expressive speech and social skills). I’ve applied for a TK spot for him, but our local school doesn't offer TK, and he has been waitlisted at all the schools that are a reasonable distance from us. Not being optimistic about a spot opening up, I’ve signed him up for another year at his preschool. We’re considering hiring someone to give him one-on-one support for a few hours per week at school. I would love to hear from others who have been through something similar, what your experiences were, and if you have any recommendations! Thank you in advance!