The disposition of a child and evidence adduced in a hearing in the juvenile court may not be used against such child in any proceeding in any court other than for a proceeding for delinquency or unruliness, whether before or after reaching majority, except in the establishment of conditions of bail, plea negotiations, and sentencing in felony offenses; and, in such excepted cases, such records of dispositions and evidence shall be available to district attorneys and superior court judges and the accused and may be used in the same manner as adult records.