Can children eat fleishigs during the nine days? Is Erev Shabbos any different?

Kids under six may eat meat in the nine days.

On Erev Shabbos, even older kids may eat if it’s close to Shabbos when they normally eat as they will be going to sleep later.

שו”ת אגרות משה או”ח ח”ד סי’ כ”א אות ד’.