import matplotlib.pyplot as plt

plt.rcParams["figure.figsize"] = [7.50, 3.50]
plt.rcParams["figure.autolayout"] = True

data = [3, 5, 1, 7, 9, 5, 3, 7, 5]
_, _, patches = plt.hist(data, align="mid")

for pp in patches:
   x = (pp._x0 + pp._x1)/2
   y = pp._y1 + 0.05
   plt.text(x, y, pp._y1)

plt.show()