Taking number in between for interpolation

In D9
=IFERROR(INDEX(A$2:A$7,MATCH($D$10,$A$2:$A$7,0)),INDEX(A$2:A$7,MATCH($D$10,$A$2:$A$7,1)))

In D11
=IFERROR(INDEX(A$2:A$7,MATCH($D$10,$A$2:$A$7,0)),INDEX(A$2:A$7,MATCH($D$10,$A$2:$A$7,1)+1))

In E9
=INDEX(B$2:B$7,MATCH($D9,$A$2:$A$7,0))
Copy down and across