Is there a genetic test that shows who is at risk for osteogenic sarcoma?

Not really. Unless your family has a documented history of this, and a particular mutation has been identified in other family members, there is not an established test for this condition.
OS and gene. Some of the sarcomas can run in families and clusters. Some of them can present with other malignancies in family. I think gene testing for p53 mutation can be done if there are other types if cancers besides os. There is no specific genetic test for os.