Palo Alto-based Hewlett-Packard reported a 9% increase in net revenue and a 5% rise in net earnings for the fiscal year ended Oct. 31. In the fourth quarter, revenue increase 15% and earnings 23%, compared to the same period in 1985. Fourth-quarter results were highlighted by improvements in the rate of order growth, both domestically and internationally, a spokesman said. In addition, the company's expense- and cost-control efforts continued during the fourth quarter, with more than 1,500 employees in the United States electing to leave under either the company's voluntary early-retirement program or voluntary-severance plan. Overall, the firm said it saw encouraging signs of strength in many of its product areas, including medical, analytical, computer peripherals and service products, with expectations that the trend will continue into early 1987.