Thanks for the answer!
I got the problem solved, so here is the code:
import numpy as np
import tflearn
from tflearn.data_utils import load_csv
from numpy import genfromtxt
data, target = load_csv('boston_train.csv', has_header=True)
target = np.reshape(target, (-1,1))
net = tflearn.input_data(shape=[None, 9])
net = tflearn.fully_connected(net, 9)
net = tflearn.fully_connected(net, 1)
net = tflearn.regression(net, optimizer='sgd', loss='mean_square', learning_rate=0.01)
net = tflearn.DNN(net)
net.fit(data, target, n_epoch=10, batch_size=10, show_metric=True)
test_data = genfromtxt('boston_predict.csv', delimiter=',', skip_header = 1)
test_data = np.reshape(test_data, (-1,9))
pred = net.predict(test_data)
print(pred)