Yes start from day 9 or 10 but do twice a day on in morning one evening. Because peak happens suddenly. So yes do it .
I read somewhere that we always have a low level of lh in our bodies hence there always being 2 lines but you're looking for the test line to be darker than control.
I use a brand called Easy at Home (by Premom- terrible name if you ask me). It comes with an app to read the strips, which helps. I usually test from day 9 or 10, around 11 am and then 7 or 8 pm (no morning urine apparently). Try to stop drinking a couple of hours prior. The peak is usually only on one strip, for me around day 13, and it only lasts a few hours, but you should be able to catch it this way. I keep having a 2nd faint line anyway, so I test once more the day after and then stop
When it comes to ovulation tests, there will always be a second line. Your peak is when the test line is darker than control line but at times its hard to determine if its darker or not. I would say starting now is not a bad idea because you can watch the progression. Hope that helps