Stopping there for one day on our cruise. We probably won't do an excursions unless there are unreal but any must see or a great lunch spots? (we will have a 9 & 5 year old with us)

It's a solid 1:30 round trip. I wouldn't do it. I'd go to the beach. Progreso is a port town w alot to do.

Malecn Playn & Playa Progresso are all right next to the cruise pier.

For food:

Crabster
Mobula
Slicer
Scappata
Maasai Mayan
Marymar Beach Club
Cristo Rey

If You want to go just out of Progresso, Isla Columpios
There's also a pink lagoon mayan Salt mine: "Meya'h Ta'ab" Charcas Rosas - Pink Lake that's pretty cool. The pink lagoon is what gives the flamingos their pink color.
You can also go to Xcambo Mayan Ruins/Temple. The Mayan Temple and Salt lagoon are about 35 minutes out of town but very close to each other.

Go to Maya-Ka. Their Don Julio Reposado marg was of the best Margaritas I've ever had, anywhere. Even better, it was only 95 pesos. The ambience is really cool and it was a much better experience than the crowded beach clubs in Costa Maya/Cozumel in my opinion.

I think a lot of people drag Progresso because it's more run down than Cozumel or Costa Maya, but I personally liked getting out and walking along the boardwalk. You do have to take a bus from the cruise ships to the town since it is a shallow water port, but that didn't bother me.

There's also a cool looking museum that I want to go back to if we ever get back to Progreso. It's called El Museo Del Meteorito; Progreso is right near where the meteor that wiped out the dinosaurs hit. The Museum gets mixed reviews online though, so you might want to do some research on it before you spend money. It just looked cool when we walked past it.