SELECT c.EmailAddress,
o.BillingFirstName AS WC_FirstName,
o2.LatestOrder
FROM Customers c
JOIN orders o ON o.customerid = c.customerid
JOIN
(SELECT
cx.EmailAddress,
MAX(o.OrderID) AS LatestOrder
FROM Customers AS cx
JOIN Orders o
ON o.customerid = cx.customerid
WHERE o.OrderStatus <> 'CANCELLED'
AND o.OrderDate > '09/01/2017 00:00'
GROUP BY
EmailAddress) AS o2 on o2.EmailAddress = cx.EmailAddress
GROUP BY c.EmailAddress,
o.BillingFirstName