Did Haiti make a deal with the devil to gain independence?

No.

Obviously they did not from the secular perspective of not believing in spirits.

But they also obviously did not from a Christian perspective.

Souls are individual things, not collective entities. There is no "group soul", and no leaders in 1804 could trade "all Haitian souls" for "independence". The most any individual leader could have done is offer his.

It is known that a popular televangelist did claim such a mean thing, but no other mainstream church or competent theologian supports this.