Criminal Judicial Administration Act of 2021 This bill expands the authority of federal judges to reimburse defendants for expenses related to attending court proceedings. The bill also broadens the authority of magistrate court judges. Currently, when a defendant is released pending further court appearances, federal judges may order the U.S. Marshals Service to provide transportation and subsistence (food and lodging) expenses for a defendant to travel to court appearances, but not expenses during or to return home from such court appearances. This bill allows federal judges to order the Marshals Service to provide a defendant's transportation and subsistence expenses to return home from court proceedings, as well as subsistence expenses during such proceedings. Additionally, the bill authorizes magistrate court judges to rule on post-judgment motions pertaining to misdemeanor cases they tried and disposed of. Current law permits magistrate judges to try and dispose of misdemeanors in the district courts if the defendant consents.