I want to make and If statement which will work when a double "credits" is between 1 and 9. But I'm not sure how to. Will

If (1 <= credits => 9) Then


have you tried it?
anyway, If, with capital I and Then are not from Java, so no.
for a double condition, try either nested ifs:

if ( condition1 ){
  if ( condition2 ){
    // your code

or, put the conditions in one statement:

if ( condition1 && condition2 ){
  // your code

for more basic information on the if statement:

Thank you for your reply.
The second option you mentioned I prefer better, so if I state:

double credits;
if (credits >= 1) && (credits < 9) {
//my code

It will work, right?

You're missing a set of brackets round the whole condiiton, but otherwize that's good.
ps It's usually quicker to try something simple like that yourself than to wait for someone to reply to you.