Save Children's Coverage Act This bill allows states to provide for extended coverage under Medicaid and the Children's Health Insurance Program (CHIP) of children after the end of the COVID-19 public health emergency. It also allows for extended Medicaid coverage of certain low-income, formerly homeless, or formerly incarcerated adults. Specifically, after the emergency period ends, states may provide for continued Medicaid or CHIP coverage of children under the age of six until the child turns six or is no longer a resident of the state, whichever is earlier. For children ages 6 to 18, the state may provide for continued coverage for two years after the child is deemed eligible, until the child turns 19, or until the child is no longer a resident of the state, whichever is earlier. States may also provide for continued Medicaid coverage of adults whose income does not exceed 28% of the federal poverty line or who were homeless or incarcerated in a prison or psychiatric hospital within the two years prior to applying for Medicaid; coverage may be provided for 12 months after the individual is deemed eligible or until the individual is no longer a resident, whichever is earlier. The bill also requires states to annually review the demographics of Medicaid enrollees, including contact information, as a condition of receiving a waiver from Medicaid requirements (e.g., Section 1115 demonstration waivers) after the emergency period ends.