The perimeter=sum of sides=9x+9=9(x+1). There is no other property of the triangle to equate an expression of x. The perimeter or area value would be sufficient. For example, if the perimeter was 72, x=7 (25,19,28).
If the triangle is isosceles then AB=AC, AB=BC or AC=BC. This would enable us to calculate x (AB,BC,AC) respectively: 4 (16,13,16),1 (7,7,4), 2.5 (11.5,10,10).
If the triangle is right-angled, there are no rational solutions for x.