You can and should move to have them sealed and destroyed. You will want to then follow up with the police departments to make sure they have done it if you get such an order.
Yes, under Welfare and Institutions Code sections 781 and 781.5, your son can request this for each case (although in juvenile court, multiple cases all have the same case number for the same person).
There is a government form that he will want to complete and submit to the court to request this. It is a one or two page form. The court clerk should be familiar with this form and give it to your son to complete. Good luck.
Police departments, divisions and even individual officers and teams of officers (such as CRASH units) often make and maintain (for years) informal notes and records of encounters with juveniles and referrals to social services and law prosecutorial agencies. These are commonly called "FI's" or Field Investigation notes. These materials are not encompassed by motions to juvenile court re sealing of juvenile court records. I add this information to the responses you have received here because of your description of the source of your information. Typically, F.I.'s are obtainable through discovery processes in family law actions, civil rights cases and other legal proceedings.
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