query slower on 9.3 simplified a little bit.

SELECT mo.referencia,
       ent.unidades AS entrada,
       ven.unidades AS vendidas,
       taprov.precio

FROM modelo AS mo

   JOIN (SELECT mo.modelo_id AS id_modelo,
                SUM(lin.unidades_reales)::int AS unidades,
                MIN(cab.time_stamp_recepcion)::date AS min_fecha

         FROM modelo AS mo
            JOIN articulo AS art ON art.id_modelo = mo.modelo_id
            JOIN albaran_entrada_linea As lin ON lin.id_articulo = art.articulo_id
            JOIN albaran_entrada_cabecera AS cab ON cab.albaran_id = lin.id_albaran

         WHERE cab.id_almacen_destino = 109

         GROUP BY mo.modelo_id

         HAVING MIN(cab.time_stamp_recepcion)::date = (current_date - interval '30 days')::date ) AS ent ON ent.id_modelo = mo.modelo_id

   JOIN (SELECT mo.modelo_id AS id_modelo,
                (CASE
                   WHEN SUM(tic.unidades) > 0
                      THEN  SUM(tic.unidades)
                   ELSE 0
                END)::int AS unidades
         FROM modelo AS mo
            JOIN articulo AS art ON art.id_modelo = mo.modelo_id

            JOIN (SELECT lin.id_articulo,
                         SUM(lin.unidades) AS unidades

                  FROM ticket_cabecera AS cab
                     JOIN ticket_linea AS lin ON lin.id_ticket = cab.ticket_id
                                              AND lin.tienda = cab.tienda

                  WHERE cab.tienda = 109
                  GROUP BY lin.id_articulo) AS tic ON tic.id_articulo = art.articulo_id

       GROUP BY mo.modelo_id) AS ven ON ven.id_modelo = mo.modelo_id

   JOIN tarifa_proveedor_modelo_precio AS taprov ON taprov.id_modelo = mo.modelo_id
                                                AND taprov.id_tarifa = 3

WHERE mo.id_seccion <> 4
  AND (ent.unidades <> 0 OR ven.unidades <> 0)

ORDER BY referencia;