If under 5 childcare is recorded as being provided by the school in the childcare details it is expected that the provision is greater than 9 hours.
Childcare for children aged between 0 to 4 years (Under 5): By this, the DfE means a service that parents can use for at least 9 hours a day if they choose to. Do not include provision that is only available during school hours or where children can only attend for a morning or afternoon session. Most schools therefore will record No for Under 5 childcare provision.
If you go to the Data Items section of the DfE guidance here and click on School Childcare, you will receive confirmation of this.
To amend this go to Admin > Census > Spring 2021 > Childcare Details (in the Spring 2021 Census Specific Data).
In this area click edit next to the under 5 entry, amend the opening and closing times to reflect at least 9 hours. Then click update to save.