Re: Kurama is only using half its power.?.?.?
In terms of answering the OP's question, Naruto is at full power as we know so far even though he only has one half of Kurama's chakra sealed within him. The question should be...is Kurama at full power? Well that isn't so easy to answer so there is still some things we do not understand or have not been fully explained.
We are unsure as to how the sealing of his Yin chakra has affected Kurama aside from his size and if Naruto had access to the full chakra (Yin/Yang) of Kurama sealed in him, how it would affect him at all. I doubt he has replenished his Yin chakra being in Naruto.
This is what's stated on the Naruto wiki page for both Yin and Yang release:
The Yin Release (陰遁, Inton; Viz "Dark Style" or "Shadow Style") techniques, based on the spiritual energy that governs the imagination, can be used to create form out of nothingness
The Yang Release (陽遁, Yōton; Viz "Light Style") techniques, based on the physical energy that governs vitality, can be used to breathe life into form
The reason why Yamato's wood techniques reacted when Naruto was in his initial nine tails mode (just after Naruto fought Kurama in his subconscious) was because he only had the Yang chakra of Kurama, I wonder if he had Yin release then how would it have the same effect? We also have to remember that Naruto has poor chakra control, this stems from the fact that Kurama is sealed within him. It's the reason why he still requires extra hands (shadow clones or chakra hands) to create the Rasengan and/or Rasenshuriken, if he did not have Kurama sealed within him then it is quite possible he'd be able to do more without having to create shadow clones.
I wonder if Naruto is able to combine Kurama's Yang and his own Yin release somehow? This would counter that fact that Kurama's Yin release is sealed away permanently but not sure if it's even possible.
Also the difference between Naruto and Kushina is that Kushina had 'special chakra' which made her suited to become the next container for Kurama, I do not think Naruto has this same sort of 'special' chakra.
Plus this could also be the reason why when Naruto 'transforms' into Kurama, his in that chakra form and not full form that Bee is in but this is something I am unsure about.