There is no public transportation to Section 10 of MacLehose Trail. If you like, you may hike Section 9 and 10 together.
One possible way:
Take MTR to Tsuen Wan station.
Take Bus 51 running from Tsuen Wan and get off at Tsuen Kam Au(荃錦坳).
At the end point of M-trail, take Bus 60X or 60M to Kowloon or minibus to Yuen Long, Tsuen Wan.
There are more possible ways to get out from Section 10, please check it here.