As of now, I am a boy but want to be a father when I grow up and want my child to have some freedom. Is this allowed?
Islam teaches us to:
يأمرون بالمعروف وينهون عن المنكر
enjoin what is right and forbid what is wrong
And encouraging one's child to become a disbeliever is the opposite of that.
In Islam the parents' duty is not to provide their children freedom but to educate, train and prepare them for betterment in both this life and the next. Instructing children about religion is one of their duties:
يابني إن الله اصطفى لكم الدين فلا تموتن إلا وأنتم مسلمون
O my sons, indeed Allah has chosen for you this religion, so do not die except while you are muslims.
يا بني أقم الصلاة وأمر بالمعروف وانه عن المنكر واصبر على ما أصابك
O my son, establish prayer, enjoin what is right, forbid what is wrong, and be patient over what befalls you.
وأمر أهلك بالصلاة
And enjoin prayer upon your family
Also according to Islamic beliefs, non-muslims go to hell for eternity:
والذين كفروا لهم نار جهنم لا يقضى عليهم فيموتوا ولا يخفف عنهم من عذابها كذلك نجزي كل كفور
And for those who disbelieve will be the fire of Hell. [Death] is not decreed for them so they may die, nor will its torment be lightened for them. Thus do we recompense every ungrateful one.
إن الله لعن الكافرين وأعد لهم سعيراً خالدين فيها أبداً لا يجدون ولياً ولا نصيراً
Indeed, Allah has cursed the disbelievers and prepared for them a Blaze. Abiding therein forever, they will not find a protector or a helper.
And parents have been commanded to save their families from it:
ياأيها الذين آمنوا قوا أنفسكم وأهليكم نارا وقودها الناس والحجارة عليها ملائكة غلاظ شداد
O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones, over which are [appointed] angels, harsh and severe
For someone who truly believes in Islam, loves Allah and loves their children, it would be unfathomable to let their children disbelieve.