With a little homework you can see:
Isaiah 64:8 (NIV):
Yet you, LORD, are our Father. We are the clay, you are the potter; we are all the work of your hand.
Psalms 95:6 (NIV):
Come, let us bow down in worship, let us kneel before the Lord our Maker
Psalms 100:3 (NIV):
Know that the Lord is God. It is he who made us, and we are his people, the sheep of his pasture
Jeremiah 51:19 (NIV):
He who is the Portion of Jacob is not like these, for he is the Maker of all things, including the people of his inheritance, the Lord Almighty is his name
So in the OP verse, Isaiah 45:11, it should be clear that and his Maker, the maker of Israel, is another reference to God, the one and only God, the subject of the sentence in this verse. And it should also be clear from these verses that viewing God as our creator, our maker, is an OT theological tenet.
The OT books are uniformly about the unity and singularity of God, so any OT translation that looks like it might remotely be hinting otherwise needs careful review.
The MT for this verse is:
כֹּה אָמַר יְהוָה קְדוֹשׁ יִשְׂרָאֵל וְיֹצְרוֹ הָאֹתִיּוֹת שְׁאָלוּנִי עַל בָּנַי וְעַל פֹּעַל יָדַי תְּצַוֻּנִי
The verbs אָמַר, sayeth, שְׁאָלוּנִי, question me, תְּצַוֻּנִי, you would command Me are all singular. The noun forms בָּנַי, my sons, פֹּעַל יָדַי, the work of my hands are singular.
The and in and his maker is necessary in Hebrew (וְיֹצְרוֹ) to prevent the his in his maker from referring to God, as if Israel created God, but this and is superfluous and confusing in the English translation, as the OP indicates. It appears that the NET translators recognized this problem and left out the and for clarity. Yet another example of how over-literal translations can confuse readers.
So, there really isn't any way, or reason, to read his maker as an additional subject persona.