There is no standard format. Some vendors also include time.
The day of the week can be derived from the date using a function. The argument of the function is the date and the returned value is a number that corresponds to the day of the week.
I am an end of day oriented. The day of the week was available for years with CRBcharts but it has recently been replaced by PowerSignals without this option, thanks.
I just go by date. I know that when you have eg. 19/9/8, and it is followed on the next candle by 22/9/8 that 19 was a friday and 22 was a monday. Thats enough for me.