Answer:
To gush over in praise.
Step-by-step explanation:
In this text, we learn about the reaction of some of the characters in the story (his grandfather, Mr. and Mrs. March, John and Meg, Jo and Beth) to one other character that is not mentioned by name. We know that this character is a boy, and we see that all of these people sincerely admire him, and tell him so. Therefore, we can conclude that the word "exulted" in this context means "to gush over in praise."