Not sure there is such a shape.
In order to satisfy the Euler characteristics, the shape must have 8 faces and so is an octahedron. But there seems to be no octahedron with 9 vertices.
nonagon
a shape that has 9 faces
There can be no such shape.
An octagonal pyramid.
The shape would be impossible. The faces and vertices have to add up to two more than the edges.
A triangular prism.
A nonagon has 9 edges.
nonagon
a shape that has 9 faces
A nonagon.
A triangular prism would fit the given description
In a regular hexagon, you can draw a total of 9 distinct lines connecting the vertices. This is achieved by connecting each vertex to every other vertex, resulting in 6 edges and 3 diagonals. Specifically, each vertex connects to 3 other vertices not adjacent to it, leading to a total of ( \binom{6}{2} = 15 ) lines, which includes the 6 edges. However, if you only consider the diagonals, there are 9 lines.
A triangular prim has 5 faces, 6 vertices and 9 edges. A base is the same as a face.
a nonagon a shape with nine edges is called a nonagon. just like pentagon and decagon a shape with nine edges is called a nonagon. just like pentagon and decagon
5 faces (sides) 9 edges 6 vertices
Nonahedron
An octagonal pyramid