Changing date created of bulk files to 9 hours before I have 3000 files which all have different dates in which they were created. For example a file has a date created timestamp of: 1 August 11:05. How can I use the terminal to change the timestamp to 9 hours earlier: i.e. 1 August  2:05?
To do that, you need to open the 'Terminal'

In your Terminal, enter the following command:

touch -t YYYYMMDDhhmm.ss (DON'T press enter yet)

replace YYYYMMDDhhmm.ss by it's respective characters

So for example:
touch -t 197512232000.23 (DON'T press enter yet)

Locate the files you want to change their timestamps in Finder

Select all the files you want to modify and drag them into your Terminal and now, press enter

The timestamps are now changed.