Thank you for writing.
Here is good background
https://turf.umn.edu/news/creeping-charlie-management-and-value-pollinators
Fall is the best time for herbicides.
 https://extension.umn.edu/weeds/ground-ivy
Creeping charlie is more of a sign of how a lawn is managed. It is shallow rooted (grass can have deep roots that can choke out creeping charlie). 
CC prefers shade. The legacy lawns here are mostly Kentucky Bluegrass that prefers sun and is non competitive in shade. 
Both CC and Bluegrass thrive with lawn fertilizers but the grass fertilization needed to sustain Bluegrass are even more advantageous to CC. 
So, to shift the balance. Do the following.
To induce the grass to get deeper roots, set your mower as high as possible, cut off only a third and let the clippings lie. 
To water the subsoil where the grass roots go, rather than the soil surface where CC roots spread, water thoroughly once a week rather than short superficial sprinklings.
To get a grass that can more robustly compete with CC, buy a grass seed mix from a garden store that is labled for shade or is fescue seed.