Is delaying one's return home after university—with the intention of having breakfast, performing the Duha prayer, or visiting a friend—considered disobedience or an act of undutifulness towards a mother who commanded one to go home directly?

Obedience to parents is obligatory in what is good, based on the Almighty's saying: "And your Lord has decreed that you shall not worship except Him, and to parents, goodness," and the Prophet's (peace be upon him) saying: "Your mother, then your mother, then your mother, then your father." If your mother has a valid reason for her command to you, such as her need or her fear for you, then her obedience is obligatory. However, if she has no valid reason, you are not considered disobedient by contradicting her. Nevertheless, you should consider her feelings with kindness and good treatment. Obedience to parents in permissible matters depends on assessing what is beneficial. If the benefit lies in disagreeing with them, then there is no harm.