looking for ideas for a 9 day road trip from NY in August

Starting where?

OOPS saw it in the title. Is that New York City?

In August you might want to go north through New England. It's hot in the South that time of year. Do you want beach time?

Head over to Niagra Falls
then on to Cedar Point, OH(best Roller Coasters in the world)
Maybe Cuyohoga National Park

OR

Drive to Boston and see a bit there. Then on to Acadia National Park.

Philadelphia, a bit of Washington, Shenandoah National Park,

I meant to put an OR between Boston segment and the Washington segment

thanks for your replies - to clarify, I will be driving from Long Island and I had been looking for ideas that are child-friendly and fun. We have been to Niagra Falls and Toronto twice, so that is out. We have been to Boston a few times, but have gone no further north. Any tips how far North to go in the direction of Maine/Acadia or if we should attempt to head toward the Great Lakes ( which I had not previously considered)?

Drive down the Garden State, take the Cape May Ferry to Lewes DE, then continue south to Chincoteague. Do some beaching, see the wild ponies for a few days.

Next continue south over the bay bridge then go to Williamsburgh/Yorktown/Jamestown for a few days. Do a bit of history and if the kids are into amusement parks, hit 6 flags.

If you are hitting amusement parks don't forget to go to Knobel's Grove. http://www.knoebels.com/index.php
The carousel is now 100 years old. My kids loved grabbing the rings on the way by. The Phoenix roller coaster is one of the nicest wooden roller coasters anywhere.

I think New England is a great idea. Lots to do and not that far from NY. Head for a sandy beach? The waterpark in Hampton NH is great fun. York ME is a popular family destination with sandy beaches, a small amusement park, lighthouse, etc. The coast gets rocky north of Portland.
From Portland you can be in NH's White Mountains in about an hour. Hike to a waterfall? Try some zip lines. Visit Clark's Trading Post/trained bears. Take a tram ride. Visit the Flume or Lost River.
In August, rivers can be low so you might consider a family kayak trip. But with a 3 yo maybe too young. There are rental places throughout New England.
Heading south on I93 in NH you could spend a last day at Canobie Lake Park (amusement rides) or
Continue west to Danville VT's Great American Corn Maze. Go south on Rt 100. There's a website for popular swimming holes in VT. We picnicked at one. You could walk across the river at one point (but need water shoes, rocky bottom) but upstream there was a deep pool, small waterfall and kids were jumping off the ledges into the pool. (had to be a good swimmer)

thank you all!