When does the balance of credit card actually get reported to CRA?
Generally most creditors report the balance at the same they issue your monthly statement. A few creditors like US Bank report what the balance is at the end of the month. Also a few creditors like Chase will update your balance to the credit reporting agencies in between monthly statements.
Most CC issuers report the "Amount Owed" at the top of your monthly statement. They do so generally within 24 hours of that statement date.
A much smaller minority of CC issuers (US Bank, for example) reports whatever your CC balance is on some fixed day of the month -- irrespective of what your statement said. Thus, for US Bank, your statement could print on Aug 23 with a balance of $235, and then you make some more purchases, with a balance of $415 as of Sept 1. The $415 figure would be reported on Sept 1 if you had a US Bank card. (Most other CC issuers would report the $235 figure.)
Regardless of the date that the CC issuer reports a new balance to the three CRAs, it then takes 1-7 business days for the CRA to update that new balance inside its database. (That's business days, not calendar days.) A week of calendar time (or a bit less is common.)