Yes, 8/8 is considered an improper fraction. An improper fraction is defined as a fraction where the numerator (the top number) is greater than or equal to the denominator (the bottom number). In the case of 8/8, the numerator and denominator are equal, which still fits the definition of an improper fraction.
Improper fractions can be converted into mixed numbers. For example, 8/8 can be simplified to 1, which is a whole number. However, it is still classified as an improper fraction because it meets the criteria of having a numerator equal to or greater than the denominator.