If I pour Sherry on top of my Lobster Bisque Soup, will it curdle ? Is it dangerous?

just make sure your sherry isn't ice cold and you should be good to go. usually curdling occurs with milk bases and alcohol when the milk is cold and the alcohol is not. but i supposed it could go the other way too although its never happened to me, when i cook with alcohols i have them at room temp to avoid that. Sounds like you are going to have a yummy snack.

If it's not cold sherry then it should be fine. If you're making this from scratch, you'd want to add the sherry earlier in the cooking, so it has a time to burn off the alcohol, and leave the flavor of the wine.

Most of the time, curdling happens when you add something acidic to cream or milk.

Should be fine. Just do a wee bit, though (a tsp) so it doesn't overpower it.