Just use a plain array ...

use warnings; use strict;
use Data::Dumper;
$Data::Dumper::Indent = 1;

my $spec = '1-4,9-11,6,8,3,2';

my @out;
my %seen;
for my $range ( split ',' , $spec )
{
  my @range = split '-' , $range;

  push @out
    , map
        {
          #  Subtract for array indexing.
          my $k = $_ - 1 ;
          #  Uniquify (keep only the numbers unseen).
          ! $seen{ $k }++ ? $k : ();
        }
        scalar @range == 1
          ? @range
          : $range[0] .. $range[1]
          ;
}

print Dumper( \@out );
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