Your equation implies (to me) that y is a function of x, not t. So your function should probably be:
function [dydx] = odefun(x,y)
Also, there is an error in this line at the very end:
dydt=[y(2); pi*y(1).*exp(x/3)*2*y(2)*sin(pi*x) + x*y(1)*cos(pi*x) - (y(1)./9)x];
You might want:
dydt=[y(2); pi*y(1).*exp(x/3)*2*y(2)*sin(pi*x) + x*y(1)*cos(pi*x) - (y(1)./9).*x];
or some other operator, since MATLAB will throw an error without an operator there.
When I ran it (with the change in the function line, vectorising, and putting a multiplication operator before the x at the end, it ran.
