As you can see from the two links below, we simply do not know whether poverty plays any major role in causing people to get involved in terrorism. There are people who believe passionately in the idea that poverty does cause terrorism, but there are also people who reject that idea.
Those who believe that poverty causes terrorism argue that people become terrorists out of frustration. They are not able to get ahead economically in life and this makes them frustrated and angry. They are therefore easy prey for charismatic leaders who can persuade them to go off and engage in terrorist attacks.
However, there are those who reject this argument. As one of the links below says, people who end up getting involved in terrorism are not typically poor people. Instead, they are often people like Osama bin Laden who are actually pretty well-off. To quote from the link:
But the empirical record evinces little correlation between economics and militant Islam. Aggregate measures of wealth and economic trends fall flat as predictors of where militant Islam will be strong and where not. On the level of individuals, too, conventional wisdom points to militant Islam attracting the poor, the alienated and the marginal—but research finds precisely the opposite to be true. To the extent that economic factors explain who becomes Islamist, they point to the fairly well off, not the poor. . . .
So, the answer to this is that we simply do not know because "experts" make arguments on both sides of this issue.