How to perform JOIN and only use single record for each instance on 2nd table
For future posts, it is better to provide CREATE TABLE statements and INSERT statements. It is also beneficial to add an expected result set. What I guess you are trying to do is to pair Product_Plan_Creation_Date and Product_Plan_Delivery_Date. You can create an ordering number with a WINDOW function:

SELECT Product_Plan_ID, Product_Plan_Creation_Date
     , ROW_NUMBER() OVER (PARTITION BY Product_Plan_ID
                          ORDER BY Product_Plan_Creation_Date) AS RN
FROM Products


and similar for Product_Delivery:

SELECT Product_Plan_ID, Product_Plan_Delivery_Date
     , ROW_NUMBER() OVER (PARTITION BY Product_Plan_ID
                          ORDER BY Product_Plan_Delivery_Date) AS RN
FROM Product_Delivery


Now you can use the ordering number to join these two derived tables:

SELECT A.Product_Plan_ID, A.Product_Plan_Creation_Date
     , B.Product_Plan_Delivery_Date
FROM (
    SELECT Product_Plan_ID, Product_Plan_Creation_Date
         , ROW_NUMBER() OVER (PARTITION BY Product_Plan_ID
                              ORDER BY Product_Plan_Creation_Date) AS RN
    FROM Products
) AS A
JOIN (
    SELECT Product_Plan_ID, Product_Plan_Delivery_Date
         , ROW_NUMBER() OVER (PARTITION BY Product_Plan_ID
                          ORDER BY Product_Plan_Delivery_Date) AS RN
    FROM Product_Delivery
) AS B
    ON A.Product_Plan_ID = B.Product_Plan_ID
    AND A.RN = B.RN