The answer is as far away as the documentation for print:

If you're storing handles in an array or hash, or in general whenever you're using any expression more complex than a bareword handle or a plain, unsubscripted scalar variable to retrieve it, you will have to use a block returning the filehandle value instead, in which case the LIST may not be omitted:

    print { $files[$i] } "stuff\n";
    print { $OK ? STDOUT : STDERR } "stuff\n";
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So having read that one could deduce that your statement needs to look like this:

print { $x{handle} } "Wow!\n";
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print $handles{foo};
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print $strings{foo};
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The latter was picked to work. As such,

print $x{y} "Wow!\n";
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$s = $x{y} "Wow!\n";
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If the file handle expression is non-trivial, you can't omit the curlies around the expression.

print $fh "...";
print { $fh } "...";
print { $handles{foo} } "...";

print( $fh "..." );
print( { $fh } "..." );
print( { $handles{foo} } "..." );
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print

If you read the documentation for print you will see that you have to put {} around a filehandle like that:

print { $x{ handle } } "Wow!\n";
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You're missing a lot of semicolons. I get

$ perl junk
Scalar found where operator expected at junk line 5, near ")
$x"
        (Missing semicolon on previous line?)
syntax error at junk line 4, near ", ..."
Execution of junk aborted due to compilation errors.

But I'm using a very modern perl, 5.14.1

print $x{handle},"\n"; is valid to STDOUT
print {$x{handle}} $x{handle},"\n"; FILEHANDLE $x{handle} with value $x{handle}

I think the idea was to make the "normal", "usual" syntax as easy as possible, even if this caused some trouble in less common cases.

#!/usr/bin/perl -l

use strictures 1;
use Data::Dumper::Concise;

my $fh;
my %x;
$x{'handle'} = $fh;
open $fh, '>-';
print Dumper($x{'handle'}), "Wow!";
close $fh;
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