Vedas are studied through Vedangas. Vedangas are limbs of Vedas. There are six vedangas. The six Vedangas are Siksha, Chhanda, Vyakarana, Nirukta, Jyotisha and Kalpa.
Hence study of Vedas is incomplete without Jyotish (science of Astrology)..
Here are some refrences from Vedas:
RV3.54.19 May the Gods' envoy, sent to many a quarter, proclaim us sinless for our perfect safety. May Earth and Heaven, the Sun, the waters, hear us, and the wide firmament and constellations.
Here is the word 'hear us' which certainly represents a method of astrology.
RV1.50.2 The constellations pass away, like thieves, together with their beams, Before the all-beholding Sun.
This verse is the core of vedic astrological doctrines where movement of constellations are calculated with respect to earth
By Soma are the Adityas strong, by Soma mighty is the earth. Thus Soma in the midst of all these constellations hath his place. RV10.85.2
This verse is the core of vedic astrological doctrines which makes Moon lord of the constellation/ nakshtras.
“Dawn is the head of the sacrificial horse. Heaven is his eye. The year is his soul. His form are the nakshatras and the stars are his bones”. Taittiriya Samhita of Yajur Veda VII 5.25
Atharva Veda in 19.7 mentions the name of 28 constellation/ nakshtras.
Atharva Veda 19.7
A Prayer to the Lunar Mansions and other Powers for protection and prosperity
1The brilliant lights shining in heaven together, which through the world glide on with rapid motion. And Days, and Firmament with songs I worship, seeking the Twenty-eight-fold for its favour.
2Krittikās, Rohinī be swift to hear me! Let Mrigasiras bless me, help me Ārdrā!
Punarvasu and Sūnritā, fair Pushya, the Sun, Asleshās, Maghā lead me onward!
3My bliss be Svāti and benignant Chitrā, my right First Phalgunis and present Hasta. Rādhas, Visākhas, gracious Anurādhā, Jyeshthā and happy starred uninjured Mūla.
4Food shall be earlier Ashādhas grant me; let those that follow bring me strength and vigour; With virtuous merit Abhijit endow me! Sravana and Sravishthās make me prosper.
5Satabhishak afford me ample freedom, and both the Proshtha-padas guard me safely. Revati and the Asvayujas bring me luck, and the Bharanis abundant riches!
1Benign to me be all those Lunar Mansions to which the Moon as he moves on doth honour.
Similarly Brihad Aranyaka Upanishad of Yajurveda in VI-iii-1:
He who wishes to attain greatness (should perform) on an auspicious day in a fortnight in which the moon waxes, and under a male constellation, during the northward march of the sun,
Benefitting something using position of planets and star is a part of horoscopic astrology.
Valmiki Ramayan is considered Adi-Kavya, the first written book in Sanskrit. Vedas aren't considered written they are considered revealed. See how sage Valmiki describes birth of Lord Rama in Ramayana.
ततो यज्ञे समाप्ते तु ऋतूनाम् षट् समत्ययुः |
ततः च द्वादशे मासे चैत्रे नावमिके तिथौ || १८-८
नक्क्षत्रे अदिति दैवत्ये स्व उच्छ संस्थेषु पंचसु |
ग्रहेषु कर्कटे लग्ने वाक्पता इंदुना सह || १८-९
प्रोद्यमाने जगन्नाथम् सर्व लोक नमस्कृतम् |
कौसल्या अजनयत् रामम् सर्व लक्षण संयुतम् || १८-१०
विष्णोः अर्धम् महाभागम् पुत्रम् ऐक्ष्वाकु नंदनम् |
लोहिताक्षम् महाबाहुम् रक्त ओष्टम् दुंदुभि स्वनम् ||१८-११
Twice six months had rolled a way since the great sacrifice was over and, in the first month of the New Year, on the ninth day of the bright fortnight, the Lord of the worlds chose to take human form and sent down half of His essence as the son of Kausalya (thenceforth to be known as Rama), the world-honored One, the crowning glory ot the grand line of Ikshwku, and the sum of all perfections. The constellation Punarvasu, of which Aditi was the regent, was chosen to preside at his birth. The Sun, Mars, Jupiter, Venus, and Saturn were in ascension in their respective houses. Aries, Capricornus, Cancer, Pisces and the Libra, Jupiter and the Moon were in conjunction ; the rising sign was Cancer. And KausalyA, shone with unparalleled effulgence, even as Aditi when she gave birth to Indra, the lord of the Shining Ones, the Vajra-wielder.
From above verse to verse translation of Valmiki Ramayana you can see that astronomy is described in horoscopic/astrological way.
Simiarly see Udyoga Parva CXLIII of Mahabharata where Karna describes omen to Lord Krishna:
Mahabharat Udyoga Parva CXLIII
All these omens, making the hairs (of the spectators) stand on their ends, indicate, O
thou of Vrishni's race, the defeat of Dhritarashtra's son and the victory of Yudhishthira. That fierce planet of great effulgence, Sanaischara (Saturn), is afflicting the constellation called Rohini, in order to afflict greatly the creatures of the earth. The planet Angaraka (Mars), wheeling, O slayer of Madhu, towards the constellation Jeshthya, approacheth towards Anuradhas, indicating a great slaughter of friends. Without doubt, O Krishna, a terrible calamity approacheth the Kurus when specially, O thou of Vrishni's race, the planet Mahapat afflicteth the constellation Chitra. The spot on the lunar disc hath changed its position; and Rahu also approacheth towards the sun. Meteors are falling from the sky with loud noise and trembling motion.
It clearly mentions position of planets with respect to constellation which is horoscopic astrology. Hence Horoscopic astrology is also a core of vedic doctrines. If character of person can be defined by planetary position, then matching two kundalis is just it's another aspect.