How can one answer a nine-year-old daughter about her mother not praying during her monthly period, especially after the daughter noticed this and interpreted it as her mother not praying and lying to her?

The minimum age for a woman to menstruate is nine years, and a girl may menstruate at this age. Therefore, the rulings of menstruation must be understood. Parents should teach their young children what will be incumbent upon them after puberty. A girl can be told that it is out of Allah's mercy that He has made a period for women during which they do not pray or fast, due to the weakness of their bodies, but they can supplicate to Allah and remember Him. Care must be taken not to lie to her or to use allusive language that she might interpret as a lie.