"Americanophile, n. and adj." - Word of the Day from the OED
Etymology: < American adj. + -o- connective + -phile comb. form, perhaps after Anglophile n., Francophile n., etc. Compare earlier Americanophobia n. A. n. A person who loves or admires the United States or its culture.
1894 N.-Y. Times 26 Feb. 3/2 He was transformed from a bibliophile into an Americanophile.
1939 Sunday Times-Signal(Zanesville, Ohio) 17 Sept. i. 4/6 The Association‥is composed of French Americanophiles and American Francophiles.
1972 C. Barnett Collapse Brit. Power v. 346 A sentimental Americanophile whose pro-American sentiments were shared by his colleagues.
2000 Publishers Weekly 4 Sept. 54/2 An Americanophile who has put America into more than one of his own novels.. adj. Characterized by love of or admiration for the United States or its culture.
1919 N.Y. Times 12 Oct. 6/1 The‥British view of our country and our people‥[is] undoubtedly Americanophile.
1942 Dunkirk (N.Y. )Evening Observer 12 Oct. 16/4 The president of Chile, whose sincere Americanophile disposition‥[is] the same as his government's.
1979 Rev. Politics 41 495 The existence of well-defined Americanophile groups is not often immediately evident.
2003 Maclean's (Electronic ed.) 21 Apr. 4 This is when Canada's national magazine should defend Canada and not be Americanophile sycophants.
Seems your little one is onto something