the nokia 7+ was come with android one so i am little bit confiused about that updates this mobile support android 9 or not.........i want to know that support or not really

Well Android One supports 2 years of OS upgrades and 3 years of security patches.

Yesterday i received the Oreo 8.1 upgrade + April security patch (Belgium)

I got mine with 8.1 and April 1 security patch OOB. Some people got 8.0 OOB