To determine the percent of householders that are NOT "White Alone Not Hispanic or Latino" at the block group level, is it appropriate to calculate B1101H / B1101?
Yes, using B11001H and B11001 will work. Your calculation would give you the % White, non-Hispanic so to get those who are not (aka Householders of Color) then you'd have to take 100% minus that value. Alternatively, you can subtract the WnH from the total to get the number for Persons of Color and divide that by the total households to get % Households of Color.