so i should get to lvl75 crafting and start making tools only on 9.0 ?
If you plan to craft tools for yourself sure. That would be a good plan. I don't know if tools are needed in 9.0, though. However its very easy to unlock second profession with leather/tailor profession. So it would be worth to go for one of those first.
i would recommend no crafting at all
healing-potions + defense-potions are likely the most viable thing to get if you go for alchemy
but the question is whether the effort to level it up to max is worth for you or not
I would partly agree on that for f2p, as the thread price is way too high in my opinion (around 380g per piece). On p2p you have a very good price of around 80g per piece. So on p2p its very viable to go for crafting tools.
You can decide for yourself if it is worth to you as AOP is right, beside tools there is not even a single useful thing you can do with other professions than alchemy.