According to google maps the distance from Santa Claus hometown to New York is 1251.55 mi.
 So if Santa travels at 80 miles per hour , 1251.55 mi / 80 miles per 1 hour it would take Santa approximately 16 hours to travel to New York. 
 So Santa must leave Finland at 5 pm to reach New York at 9 am. 
 Hope my answer would be a great help for you.