Arriving in the middle of the night, so does my 72-hours start at midnight the next day?

My family and I will be arriving in Chengdu at 12:40am on August 8th (departing from Tokyo on the evening of August 7th).
If we apply for the 72-hour visa-free transit when we arrive in the middle of the night on the 8th, does the time begin from 00:00 on August 9th?
We would like to stay in a hotel in Chengdu, and depart for Vancouver at 9am on August 11th.

Can we use the 72-hour free transit option for this trip?
Thank you.