Yes, all three verbs in Matt 8:10, Mark 6:6 & Luke 7:9 are the same Greek verb, namely, θαυμάζω (thaumazó) which occurs 44 times in the NT text. The various shades of meaning of this verb are given by BDAG as:
- to be extraordinarily impressed or disturbed by something
- (a) intransitive: wonder, marvel, be astonished (the context determines whether in a good sense or bad sense), eg, Matt 8:10, 15:31, 22:22, 27:14, Mark 5:20, 15:5, Luke 1:21, 63, 8:25, 11:14, 24:41, John 5:20, 7:21, Acts 4:13, 13:12, 41, Rev 17:7, Gal 1:6, etc
- (b) transitive: admire, wonder at, respect, eg, Luke 24:12, John 5:28, Acts 7:31, Luke 7:9, Jude 16, 2 Thess 1:10.
- Wonder, be amazed, as deponent with aorist and future passive:, eg, Rev 17:8, 13:3.
Note that Mark 6:6 and Matt 8:10 are intransitive cases but Luke 7:9 is a transitive case. Further, Mark 6:6 is an astonishment in a bad sense (because of unbelief) while Luke 7:9 and matt 8:10 is astonishment in a good sense (because of commendable faith).
Lastly, while the same verb is involved, the grammatical inflexion is slightly different in each case. All this is summarized in the list below:
- Mark 6:6 - ἐθαύμαζεν = imperative indicative active, 3rd person singular [intransitive; marveled in a bad sense]
- Luke 7:9 - ἐθαύμασεν = aorist indicative active, 3rd person singular [transitive; marveled in a good sense]
- Matt 8:10 - ἐθαύμασεν = aorist indicative active, 3rd person singular intransitive; marveled in a good sense]