When installed, CCleaner creates it’s own services entry which it sets to ‘Automatic’ (at startup) so you can also set that service to ‘Manual’ or ‘Disabled’ which will disable it from startup.
Open Windows services:
Windows key + R
Type ‘services.msc’ without quotes
OK
Scroll down to ‘CCleaner 7/X’
Double-click on entry to ‘Manual’ or ‘Disabled’
Change ‘Startup type’ as required
OK
When CCleaner is then opened, you will be prompted to start the service in order to run the program. Note that once the service has been started, it will contniue to run in the background even after the program has closed.