In my opinion, creativity is not associated with acting out behaviors. In fact some children and adults with acting out behaviors are very creative. There are no tests of which I am aware that measures acting out behaviors in this way.  

Acting out behaviors in children are more often related to a history of trauma and family violence or disorganization.  One might get information about the trauma in a child's life through creative expression.  The key then would be to provide treatment for the trauma and/or family issues.  In addition to that, children with acting out behaviors often have a low level of pro-social coping skills.  Therefore, building skills such as anger management, problem solving, self-management, and relationships are very important to reducing acting out behaviors.  You would be better served to measure the level of skills than creativity.

Dr. kathryn Seifert

I have used both creativity tests and rating scales which cover acting out behaviors, but I'm not sure how you want to connect the two. Do you want to see whether engaging in painting tends to reduce acting out behaviors? In other words, does painting have a therapeutic (calming) effect?

What is the age of the children you are speaking of? In some countries kindergarten serves 3 to 6-year-olds. In the U.S., kindergarten serves 5 to 6-year-olds.

The Child Behavior Checklist /4-18 (Achenbach, 1991) has been used in a number of countries for rating children's externalizing (acting out) and internalizing behaviors.Children's teachers and/or parents rate the children's behavior on  3-point scale. Be cognizant that "acting out" is defined differently in different cultures. Some cultures expect unquestioning obedience to elders. Other cultures encourage children to question.

The Torrance Tests of Creative Thinking (Torrance, 1991) are widely used for assessing children's creativity. However, creativity is culturally defined, so what is considered creative in one society is not necessarily viewed as creative in another society. The Torrance tests mentioned above are not appropriate for younger children (3 to 5-year-olds).

Have to be careful around the use of the terminology "acting out behaviors".   When a child is emotionally disregulated he will 'act out' but it is important to understand why, and what is going on beneath the behavior.  This could be emotional trauma, it could be sensory processing difficulties, it could be social communication challenges.  The DIR.Floortime model provides a beautiful understanding of regulation and social and emotional development and shows how understanding the child's individual profile and building trusting relationships can enhance social and emotional development.