The student had the right to deny access to the vehicle - if they wanted to get in they should have had a warrant, which would have been based on Probable Cause. But if the student said No, you cannot open and search my car then this would be a violation.
Based on the information that you have provided, I suggest that you consult with a local attorney who can work to have any charges dismissed based on the violation of the rights.
As far as a phone call to the parents, the US Supreme Court has ruled the following:
Juveniles have the same rights as adults when ARRESTED
Upon ARREST >
* The right to an attorney.
* The right to consult with parents. (The juvenile is only supposed to be allowed to waive the right to an attorney AFTER consulting with his or her parents, but the parents themselves can not waive the child's right to an attorney.)
*The right to be fully informed of exactly what is being charged.
* All of the normal rights regarding courtroom procedure, including the right to confront the accuser and cross examine witnesses, subpoena witnesses to court, keep out hearsay evidence, require the prosecution to provide you with evidence the prosecution has that might indicate innocence, the right to testify AND the right to remain silent.
* The right to remain silent at all stages of the case, even when first stopped by a police officer. (in your case the school administrators or whoever did the investigation)
* Some right to be free from unreasonable search or seizure (but the courts are very loose in determining what is a "reasonable" search or seizure when a juvenile is involved).
* Juveniles must also be kept in juvenile facility instead of an adult jail, but the functional difference between the two may be nonexistent, except that the juvenile facility has other juveniles in it instead of inmates older than 18.
So if there is an ARREST they would be allowed to consult with a parent as to whether they should have an attorney present. If he was not free to leave then there was an arrest. If he was told that he could go at anytime then there was no arrest. People often do not know when they are ARRESTED. And they do not know they do not have to participate in questioning without an attorney or for a minor a parent. Though the minor did say he wanted to have a parent present.