What is the ruling on taking a retirement pension percentage higher than what is due through “wasta” (mediation/nepotism) to cover one’s needs, knowing that a lower percentage would affect the repayment of debts and family obligations?

It is permissible to intercede (use Wasitah) if it does not involve deception, trickery, or bribery, and if it is merely a matter of influence to convince officials to increase an entitlement. However, if the intercession is a bribe, trickery, deception, or for the purpose of attaining something to which one is not entitled, then it is not permissible, due to Allah's saying: "Whoever intercedes with a good intercession will have a share from it, and whoever intercedes with a bad intercession will have a portion from it. And Allah is over all things a Maintainer." (An-Nisa:85).