Claiming a dependant child for a part year

Hello, Have a client with 4 children, one of which is disabled. In September of 2022 that child moved to the US to live with the father. Can the mother claim the child for the 9 months that he lived in Canada? She also paid for daycare for that child, same question.
Thank you

Simply reporting a child as a “dependant” doesn’t have any direct effect on the tax return (except for provincial tax deductions, which may different in each province). If you are including a S5 for that child, there are various deductions that COULD be claimed, but you need to look at the rules for each of them:

For example, the caregiver credit can be claimed only if that dependant is reported as the taxpayer’s “eligible dependent” (previously called "equivalent to spouse). The amount for an eligible dependant can be claimed “if, at any time in the year, you supported an eligible dependant and met certain conditions.”

Further, you have to consider the indirect effect of reporting a child as a dependant - that is, for CCB, CAI, and GST/HST credits. Each of these programs has their own rules, and the taxpayer may need to contact each those program departments to advise them about specific dates when the child moved in/out.