Immediate Coverage for Former Foster Youth Act This bill accelerates the application of certain changes that are scheduled to take effect under the Substance Use-Disorder Prevention that Promotes Opioid Recovery and Treatment (SUPPORT) for Patients and Communities Act relating to the coverage of former foster youth under Medicaid. Under current law, a state Medicaid program must cover former foster youth until the age of 26 if the youth were in the state's foster care system at the age of 18 and were enrolled in the state's Medicaid program while in foster care; a state may choose to also cover former foster youth from other states. The SUPPORT for Patients and Communities Act altered these provisions to require a state Medicaid program to cover former foster youth from other states until the age of 26; such changes apply to former foster youth who reach the age of 18 on or after January 1, 2023. The bill instead applies these changes to former foster youth who reach the age of 18 on or after the date of enactment of this bill.