Gabriel (1999)

Is a convent anyplace for a boy? Gabriël is a lad of about eight, probably a foundling, who lives in a convent, the only child among about 20 nuns. Except for Sylvia, a young nun, Gabriël doesn't get on well with others. He thinks of himself as an angel, impatient to grow wings and to fly, impatient with earth's rules. He's been collecting feathers from the many geese on the convent grounds. What happens next seems to horrify everyone except Sylvia, who may be in on Gabriël's secret.

Unfortunately the movie Gabriel is not yet available on HBO Max.