It's hard to say, however.. you can't use the death reaper seal as his strongest seal. He wanted to seal half of the Chakra because he wanted to give the rest to Naruto, He knew that he wouldn't be handle nor hold and suppress all of the 9 tails chakra so Minato seal half of it on purpose to seal the rest in to naruto.
Wither he is able to seal the whole 9 tails, i believe he could. That would depend of wither or not you mean inside himself or seal it somewhere else. Minato didn't want to take the 9 tail to the grave or kill or the sake of it regenerating itself and the fact that it would mean unbalanced power between the nation's.
Giving the potential and the fact that Minato was one of the best shinobi that he existed i would say he could seal it.
Edit: Miss read, i though you were talking about the 9 tails for some reason, must be getting sleepy.
He does not have the potential or the power to seal something that big. That's my opinion
