SOUTH KOREA'S 1987 GNP SEEN GROWING NINE PCT South Korea's gross national product (gnp) is forecast to grow by nine pct in 1987, surpassing the government's original forecast of eight pct and against a 12.5 pct rise in 1986, an Economic Planning Board report said. The report reviewing the country's economy in the first three months of this year said year-on-year gnp was provisionally estimated to have grown by about 12 pct in the period, against a 10.5 pct growth in the same 1986 period. Board officials said the gnp rise in the January-March period is due largely to increased exports, which totalled 9.34 billion dlrs against 6.9 billion a year earlier.