Your son almost certainly has an inmate number already assigned, even though he just arrived yesterday. The Ohio Department of Rehabilitation and Correction assigns identification numbers during the intake and booking process, which happens on arrival. The number may just not be showing up yet in the places you have been searching.
The most reliable place to find it is the Ohio DRC offender search tool at appgateway.drc.ohio.gov/OffenderSearch. Search by his name and the results will show his inmate number, current facility, and basic information about his case. The database updates as new arrivals are processed, so if he was booked yesterday, his profile should be visible or become visible within a day or two as the system catches up.
If he does not appear yet in the search results, try again tomorrow. New intakes sometimes take 24 to 48 hours to populate fully in the public-facing database even though the number exists internally at the facility from the moment he was processed in.
Once you have the number, keep it in a safe place. You will need it for setting up InmateAid services, adding money to his commissary or phone account, and any official correspondence with the facility or the Ohio DRC. It is the one identifier that follows him regardless of where he is housed within the Ohio system.
If the search consistently comes back empty after a few days, call CRC directly and ask the unit team secretary to confirm his inmate number. They can look it up immediately from their end.