Nine acres is nice, but it still is pretty close to neighbors. If in square shape, one square acre is about 70 yards x 70 yards. So nine acres would be 3 x 70 yards or 210 yards x 210 yards. That means of you are smack can in the middle, your property line is just over 100 yards in any direction.
Go with the shotgun slug, 12 gauge Deerslayer or your 20 gauge Rem 870.
Consider archery for that piece of property. Southwest Archery Spyder XL takedown recurve, about $150. Get a set of 40# limbs for hunting, and 30-35# for practice ( about $80/set). Great bow. AMO 64" smooth drawing length.
