What day do you consider “first positive OPK” to start DTD?

Hi All -
I’ve tracked ovulation the past 2 months.
Clean Blue Digital said “high fertility” on CD8, followed by “peak fertility” on CD9.
Wondfo ovulation test strip had the line about same color or a bit darker than the control line on CD9.
Also tracking using temping and charting with Fertility Friend app, and it shows CD9

Should me and H start DTD when I get a “High Fertility” on CD8 or wait to start on CD9 when I get “Peak” or should I be relying on Wondfos?

Thanks!