Yes, it is. The word for "worship" there is προσκυνέω(proskuneō).
Here's what Strong's Concordance says about this word;
From pros and a probable derivative of kuon (meaning to kiss, like a dog licking his master's hand); to fawn or crouch to, i.e. (literally or figuratively) prostrate oneself in homage (do reverence to, adore) -- worship.
Here is the outline of usage according to Thayer's Greek-English Lexicon;
to kiss the hand to (towards) one, in token of reverence
among the Orientals, esp. the Persians, to fall upon the knees and touch the ground with the forehead as an expression of profound reverence
in the NT by kneeling or prostration to do homage (to one) or make obeisance, whether in order to express respect or to make supplication
a. used of homage shown to men and beings of superior rank
i. to the Jewish high priests
ii. to God
iii. to Christ
iv. to heavenly beings
v. to demons
As you can see, the word does not primarily mean "to worship". It can be used with reference to worshipping God or worshipping others like they're God(and there's a difference between worshipping God and worshipping other people as if they're God). But its primary meaning is not worship.
So, in a summary of what Strong's and Thayer's say, προσκυνέω essentially means to express reverence, adoration, or profound respect through different actions such as prostration or kneeling. The intensity of the adoration or reverence you are directing towards an individual may vary greatly depending on the situation(e.g. who that individual is, how you regard them, etc.). That is, προσκυνέω does not have the same meaning in all possible situations where it is used. For example;
Matthew 2:2 "...saying, "Where is he who has been born king of the Jews? For we saw his star when it rose and have come to worship[προσκυνέω] him."
Matthew 2:8 "And he sent them to Bethlehem, saying, "Go and search diligently for the child, and when you have found him, bring me word, that I too may come and worship[προσκυνέω] him."
Matthew 2:11 "And going into the house they saw the child with Mary his mother, and they fell down and worshiped[προσκυνέω] him. Then, opening their treasures they offered him gifts gold and frankincense and myrrh."
Now, did the three wise men want to προσκυνέω baby Jesus in the same way they would προσκυνέω God? I can say with absolute certainty that the answer is no! Why? Because the three wise men didn't know that Jesus was God, so how could they worship him as though he is God? On top of that, King Herod told the three wise men that he wanted to worship the baby too(i.e. that he wanted to worship him in the same manner the three wise men wanted to). Did Herod know that the baby was God? What did both Herod and the three wise men know about the baby? According to Matthew 2:2, that he was the king of the Jews.
Herod and the three wise men didn't know that the baby was God, so they couldn't have worshipped him as though he was God(obviously, Herod didn't want to do any of that, but from the perspective of the wise men he did); but they did know he was the king of the Jews, so when they say they wanted to προσκυνέω the baby, what they meant was that they wanted to pay homage to the baby as the king of Jews, as a sign of reverence and adoration, not that they wanted to show reverence/adoration to the baby as if he was God Himself.
Now that we know how the word προσκυνέω can be used, let's move on to the subject of worshipping angels. In addition to Revelation 19:9-10, John προσκυνέω the angel once more in Revelation 22:8-9. It looks like John hadn't learned his lesson;
Revelation 22:8-9 "I John, am the one who heard and saw these things. And when I heard and saw them, I fell down to worship[προσκυνέω] at the feet of the angel who showed them to me, 9 but he said to me, "You must not do that! I am a fellow servant with you and your brothers the prophets, and with those who keep the words of this book. Worship[προσκυνέω] God."
Here John does the very same thing he did in Revelation 19:9-10. And here the angel tells the very same thing he told before; to not worship him, for he is but a fellow servant of John and his brothers.
John was an imperfect human, and the angel was a perfect spirit being. Humans are themselves inferior to angels.
Hebrews 2:7 "You made him a little lower than the angels; You crowned him with glory and honor;"
Despite being slightly inferior to angels, we humans are not permitted to worship angels... Or anyone else for that matter.
Acts 10:25-26 "25 When Peter entered, Cornelius met him and fell down at his feet and worshiped[προσκυνέω] him. 26 But Peter lifted him up, saying "Stand up; I too am a man."
What Peter did to Cornelius was very similar to what John did to the angel, though not the exact same. The angel reacted a little more intensely. Perhaps the kind of προσκυνέω John was giving the angel was more intense than what Cornelius was giving to Peter. After all, John did it twice in a row! In each instance, however, they made the person worshipping them get up and quit doing so. Peter's reason was that he too, along with Cornelius, is a man, and thus Cornelius should not adore or revere Paul in a manner that should lead him to fall on his feet to Peter. The angel's reason was that he was a fellow servant of John, thus he urged John to worship God instead of him.
Of course, we could easily infer that worship is not allowed to human beings by acknowledging that we are not allowed to worship angels who themselves are superior to human beings as per Hebrews 2:7. If we are not allowed to worship those higher than us, it would be absurd to think that we are allowed to worship those equal to us(as Peter said to Cornelius, he too is just a man).
This should furthermore serve as a lesson for us. If Peter treated Cornelius as his equal, being a man, not considering himself worthy of any sort of adoration or reverence, then we should carry such a mindset as well. We should always remain humble, and never let people adore us too much for the things we do or say, as though we have some special power in and of ourselves. Not that we shouldn't accept compliments or have people look up to us as role models(being a role model, someone who follows God's commandments, is always optimal); just that we shouldn't allow people to get carried away in their perception of us, never accepting special treatment(i.e. bowing at the feet of someone) as though we're somehow superior beings. Instead, we should always remember to remain humble and modest, pointing to Christ as King, Lord, and Savior of humanity, as well as to God, crediting Him for giving us His power and grace, that which truly empowers us to accomplish all we can.
In conclusion, we are not permitted to worship angels or humans; likewise, neither is permitted to accept worship from humans. Hope this helps! Have a wonderful day. :)