I think much confusion comes from miscommunication and unclear meaning of words.

Embryo -> until the ninth week after conception, inner organs are not yet present.

Fetus -> from the ninth week (heart, hands, feet, brain and other inner organs are present) until birth.

While a nine week old fetus is very small and the size of your big toe, it does grow very fast after that point. Anyway, even a nine month old unborn is still called a fetus.