Cynthia:
According to the
Magic Kingdom calendar for Saturday, April 12,
Wishes firework show will be held at 10 p.m. Because I usually give myself about 1.5 hours for a table service meal, your dinner would probably end around 7 p.m., three hours before the showing of Wishes...
Although there are a few shops at the resort that could pass the time, with little ones who might not have a long attention span, I would recommend looking for a dining time that is later in the evening if you want to see the show from the Polynesian Resort's beach (like 7:30 or 8 p.m.) If you can't get a later reservation, consider hoping on the boat at the Poly pier and making the loop from it to the Grand Floridian on to the Magic Kingdom and back to waste a solid 40 minutes. The lights of the resorts glow on the water and are sure to mesmerize the children.
I usually like to get down to the beach about 30 to 45 minutes before "show-time" so I can snag a beach lounger, but if you don't mind sitting on the sidewalk or taking a towel to spread out on the sand, you can head down to the beach nearer to its start-time.
Wishing y'all a magical vacation!
Whitney