Magento 1.9 – Display Custom Attributes Outside Product Page

In deliveries_return.phtml not find object proper object of Product.

You can try

<?php  
      echo $this->getLayout()->createBlock('catalog/product_view')->setTemplate('customstuff/deliveries_returns.phtml')->toHtml(); 
?>

and Add this code in deliveries_returns.phtml

<?php $_product = $this->getProduct(); ?>
 Delivery Times:</strong> <?php echo $_product->getshipping_times() ?></p>Delivery Costs: <?php echo $_product->getdelivery_costs() ?></p>

Try to replace the _getProductCollection method with this

protected function _getProductCollection()
{
    if (is_null($this->_productCollection)) {
        $collection = Mage::getModel('catalog/collection')->getCollection();
        $collection->addAttributeToFilter('promotion', 1)
            ->addStoreFilter();
        $collection->addAttributeToSelect(Mage::getSingleton('catalog/config')->getProductAttributes())
            ->addMinimalPrice()
            ->addFinalPrice()
            ->addTaxPercents()
            ->addUrlRewrite()
        $this->_productCollection = $collection;
    }
    return $this->_productCollection;
}

Also, if you have the flat catalog enabled, make sure the attribute promotion is marked as "Use in product listing". If it wasn't, then rebuild the indexes after setting it like that.