if ( grep { $ref == $_ } 1..8 )  { ... }

##</code><code>##

  if ( $ref >= 1  and  $ref <= 8 )  { ... }

##</code><code>##

  if ( $ref =~ /^[1-8]$/ )  { ... }

##</code><code>##

use v5.10;
use strict;
use warnings;

my @tests = qw(1 9 17 25 33);

my $range_25_32 = [25..32];   # alternatve, maybe(?) faster

for my $ref ( @tests ) {
  given ( $ref ) {
    when ( [1..8]  )      { say "A $ref" }
    when ( [9..16] )      { say "B $ref" }
    when ( [17..24] )     { say "C $ref" }
    when ( $range_25_32 ) { say "D $ref" }
    default               { say "ELSE $ref" }
  }
}

##</code><code>##

A 1
B 9
C 17
D 25
ELSE 33