Yes. As @ 乔一 from the USA says, apart from the unnecessary 'the', both of these sentences are correct. The 'Did you call..?' form, in the past simple, puts the situation in the past. The 'Have you called...?' form, in the present perfect, connects the situation to the present time. You would say this, for example, if you are still in the middle of the emergency now, and there is a sick person who needs treatment. Perhaps the other person tells you that they haven't called an ambulance yet, so you call one now. The situation is more immediate when you use the 'Have you called..?' form. In US English, there is a tendency to use the past simple in certain situations where GB English would prefer a present perfect, but both forms are used on both sides of the Atlantic. Both your sentences are correct.

A) Did you call 911 to get an ambulance? B) Have you called 911 to get an ambulance? EIther one of those is fine. Just remove "the" from "the 911". You can also shorten it to "Did you call 911?" or "Have you called 911?" Hope this helps!

In the midst of an emergency, I would ask,"Have you called 911 to get an ambulace.?" the is not necessary in either sentence. In answer A, "Did you" implies that I am asking further after the event occurred. I might ask someone telling me a story two or three days later, "Did you call 911 to get an ambulance.?" I hope that helps clarify things for you.

In U.S. English I can imagine saying either one myself. I can't quite decide which I would be more likely to say. Both are clear. Neither would be misunderstood. Neither would sound unusual.