Charizard

It would be your personel preference. Ember is way too weak when compared against WA. But If I was in your shoes, I would definitely power him up cause IVs are most valuable thing on a pokemon "according to me" and even with Ember I would have fun while using it.
So if you want to use him in gyms and want to use him in his full potantial he does not suit you.

do not power him.
You need WA/FBorFF.

And even with thos moveset, arcanine is a better choice for everything

Wing attack is much better. But hey Ember/Fire Blast is the best moveset possible for almost any other fire pokemon so there is that.

If it was me I wouldn't power it up. But if it had wing attack/FB and 100 IV I would max it out because it would be a perfect Charizard and cherish it as a collector. The lowest tier 100 IV perfect moveset mon that I powered up to the max is a Nidoqueen with PJ/EQ. I did this not for gyming but as a collector

For one, I don't power up attacking pokemon, between being able to get the upper hand with type, and the fact that the systems actually favors the attacker, I don't consider it necessary. As for battle capabilities, depends on what you are facing, if it is vs a plant or a bug, then WA/FB are better, if you are facing a steel or Ice (for god knows what reason) pokemon, then EM/FB are a better choice for charizard, in every other situation (neutral attacks), SW/FB are better. But then again, Arcanine is a better pure fire attacker.

All in all, I would power him up JUST because he's cool, even if he doesn't have the best moveset, It's a freaking 100% IV charizard. But if you only care about this in terms of battle capabilities, you really shouldn't power him up, even if he's not bad per se, there are better options (SW/FB charizard, or FF/FB arcanine).