I actually think that in this case the verb ונרצה has a subject, which is the word קרבן, which is masculine and fits perfectly the verb. We can see in the preceding verse (verse 3): אִם-עֹלָה קָרְבָּנוֹ מִן-הַבָּקָר זָכָר תָּמִים יַקְרִיבֶנּוּ, which is translated "If his offering be a burnt sacrifice of the herd, let him offer a male without blemish", and in the sequential verse (verse 5): וְשָׁחַט אֶת-בֶּן הַבָּקָר לִפְנֵי יְהוָה. So it is plainly manifest that the "son of herd (בן הבקר)" is the dominant description of the offering in verses 3-5. Furthermore, it is noticed that the word קרבן is the main subject through the whole chapter, while the word עלה comes only to decribe the kind of the sacrifice: זָכָר תָּמִים יַקְרִיבֶנּוּ (verse 5) and in verses 13 and 17: עֹלָה הוּא which is translated "it is (masculine) a burnt sacrifice". Notice especially verse 9: וְקִרְבּוֹ וּכְרָעָיו יִרְחַץ בַּמָּיִם וְהִקְטִיר הַכֹּהֵן אֶת-הַכֹּל הַמִּזְבֵּחָה עֹלָה אִשֵּׁה רֵיחַ-נִיחוֹחַ לַיהוָה, that shows that although the word עלה is mentioned, the subject is masculine (קרבו, כרעיו). So clearly the issue discussed in this chapter is the "offering" and its kinds (goat, dove, etc).
Another reason that shows clearly that ונרצה is not an impersonal verb is the continuation of the sentence: וְנִרְצָה לוֹ לְכַפֵּר עָלָיו, which means "it shall be accepted for him IN ORDER to make atonement for him." That is to say, the "thing" to be offered is a means for atonement (רצון, ריצוי) before God. It is written in the previous verse: יַקְרִיב אֹתוֹ לִרְצֹנוֹ לִפְנֵי יְהוָה, which means, he will offer IT (אותו) as a thing accepted (לרצונו) before God. Thus the same word naturally continues to function as a masculine subject in verse 4 (ונרצה לו). If it was indeed an impersonal verb, it should have described the GOAl ITSELF and not a means for the goal, which is the atonement (כפרה). The verse states clearly that the sacrifice was the thing accepted (נרצה) as a means for the atonement (כפרה ,לכפר עליו).
Here is the ultimate proof from Leviticus 19 5-7: וְכִי תִזְבְּחוּ זֶבַח שְׁלָמִים לַיהוָה לִרְצֹנְכֶם תִּזְבָּחֻהוּ. בְּיוֹם זִבְחֲכֶם יֵאָכֵל וּמִמָּחֳרָת וְהַנּוֹתָר עַד-יוֹם הַשְּׁלִישִׁי בָּאֵשׁ יִשָּׂרֵף. וְאִם הֵאָכֹל יֵאָכֵל בַּיּוֹם הַשְּׁלִישִׁי פִּגּוּל הוּא לֹא יֵרָצֶה.
The subject of these verses is זבח שלמים, a masculine noun. As in chapter one, the sacrifice is (literally) "for your acceptance (לרצונכם)" . Then Verse 7 tells: וְאִם הֵאָכֹל יֵאָכֵל בַּיּוֹם הַשְּׁלִישִׁי פִּגּוּל הוּא לֹא יֵרָצֶה. Again, we have the same verb as in chapter 1 (ירצה) in passive, relating to the masculine subject (זבח).
(Note: I need a help in editing the answer so to be more readable and clearer to understand).