You can set a session variable from a recordset row like:
$_SESSION['kidID'] = $row_WADAtbl_members['kidID'];
You can use it to insert into the database with DataAssist, or you can use it in your SQL parameters to filter results.
You can certainly echo both to the page to confirm their values as well, but remember you need session_start() somewhere above where you first start using session variables on the page.