any document about chip planner?

They will be very close, but it will always be because Chip Planner doesn't have enough info. Always rely on TimeQuest to determine if you meet timing. You mention clock network delay. When you want more info, be sure to run report_timing with "-detail full_path", so the clock network delay is broken out in detail. I am in the habit of looking at the X/Y locations in TimeQuest and not using Chip Planner at all, but I understand that is not overly intuitive and will use Chip Planner just for a nice visual.