You can decline section 8 given your need for security deposits and first, last months rent. Under current law, owners of buildings with four units or fewer can legally decline to accept Section 8 tenants. Moreover, owners of buildings with more than five units can also decline such tenants, but only if they have never accepted Section 8 subsidies.
Also, Section 8 typically pays below market rents - which is probably unacceptable to you.
The realtor is not the one to trust in this. They want the commission for finding a renter. Trust your instincts, do a credit check on all potential tenants, and check with previous landlords and employers to verify what potential tenants are telling you.