No.  WD-40 will do a couple of things - it will chase water to a degree, and
it will "remove" surface rust to a degree.  It does not remove rust though.
You can wash a bit of the oxide you see away with it and that gives the
illusion of removing the rust, but be assured that laying behind, in pits in
the steel, is more rust.  Spray it with WD-40 every day, and you won't get
rid of the rust with WD-40.  The only way to get rid of rust is to remove
the affected metal.  This can be by sandblasting if it's not too bad, (as in
your case) or by grinding out metal in more extreme cases.  The bare or
repaired area would then have to be finished in approved ways.

You can convert rust with some chemicals available over the counter.
Typical Rustoleum paint is not one of these products.  There are agents out
there though (can't think of a brand name), that will react with the iron
oxide and turn the affected area black - the sign that the chemical
conversion has taken place.  You should finish this area in normal ways
also.

Additionally, you can use a product like POR-15 which seals the rust area in
an airtight layer.  Prevent the air from getting to the area and you prevent
oxidation - rust.  POR-15 needs to be finished as well.

If you really want your car fixed the right way, take it to the dealer and
see what they'll do for you.  If you are left holding the bag, then go to a
good body shop and let them fix it.  They will sandblast the affected are to
remove the surface rust completely, will probably hit the bare steel with an
etching primer followed by an epoxy primer, base and clear coats.  Properly
done, this will be a repair that will last the life of the car, and will
match the finish of the car without the cob-job appearance of the above
mentioned approaches.

im pretty sure theres a paint defect warranty for a year..