Yes, it was Jefferson's view that the 1st Amendment erected such a “wall”, moreover the sentiment was not unique to Jefferson, as he no doubt took much inspiration from the actual author of the Amendment, Madison, who said many things along the same line. He spoke not of a wall but “perfect separation”. A wall can be dug under or gone around, a “perfect separation” is even more insurmountable.
So does anyone here think that teaching a religious doctrine in public schools should be A-OK Constitutionally? Can they teach ‘Mormon history’ of Semitic immigrants to the Americas in Utah without violation of the 1st Amendment? Could they teach Muslim religious doctrine in place of science in Deerborne Michigan without violation of the 1st Amendment?