Just because the wealthy benefitted from the plan, does not mean that the plan itself was designed to benefit the wealthy. Like John Adams, Hamilton believed that by increasing the wealth of the upper reaches of society, he would be also be increasing the lives of the ordinary people. This is essentially trickle-down economics.
This is evident in the glowing writing of American's following the economic reforms. Noah Webster, writing in Connecticut in 1791 said: "Commerce revives and the country is full of provision. Manufacturers are increasing to a great degree and in the large towns vast improvements are making in pavements and buildings." 
He knew that to build a prosperous society, he would need to leverage the greed and hunger of the upper classes. This is visible in his Federalist, No. 11. Hamilton described how the “unequalled spirit of enterprise… signalizes the genius of the American merchants and navigators and which is in itself an inexhaustible mine of national wealth.”
This is not the writing of a man out to enrich his allies and the rest of the Genting class, it is a man that identifies the need for entrepreneurs and the establishment of businesses to enrich the lowest classes.
Additionally, just because the wealthy benefitted most from the plan does not mean that it did not put the country first. The most important issue Hamilton’s government faced was guaranteeing the future survival of the union. By keeping the support of the wealthy classes and encouraging their buy-in to the federal government, Hamilton believed that he was strengthening the union. While the average person may not have enjoyed the economic benefits of Hamilton’s financial plan, they benefitted enormously from the political stability it offered.
When Thomas Jefferson entered the White House in 1801, he ordered his Secretary of the Treasury to meticulously examine treasury records to find evidence of Hamilton's corruption. But no documents were ever found that implicated Hamilton of any wrongdoing. If Hamilton was a man who was purely concerned with advancing the interests of his allies and inner circle, it is likely that he would have also engaged in corrupt activity. The fact that, even when examined with a fine-toothed comb, his actions are never once deemed corrupt would suggest that Hamilton was not a man that put himself or his allies ahead of his country.