use List::Util qw( none );

my $text = 'f000124_9019_90181234_dp';
my $sites = [ '018', '324' ];

if ($text =~ /_9(...)/, none {$1 eq $_} @$sites) {
    print "$1 doesn't match anything: to be removed..\n"
}

##</code><code>##

019 doesn't match anything: to be removed..