how to hide and display specific widget at certain time (timetable)

Try the Widget Logic plugin.

how can I put proper condition? like “show this widget only from 9 to 18 oclock”?

For daylight (from 9 thru 18), you can use this:

$hour = date_i18n('G'); if ($hour > 8 && $hour < 19 ) return true;

For dark (0 thru 8 or 19 thru 23), use this:

$hour = date_i18n('G'); if ($hour < 9 || $hour > 18 ) return true;

2 vtxyzzy: you’re genius!! it works, great thanks!