Yes, the imperative is an accurate translation.1
The text in question:
ἐγερθεὶς ἆρόν σου τὴν κλίνην καὶ ὕπαγε εἰς τὸν οἶκόν σου. (NA28)
“Rise, pick up your bed and go home.” (ESV)
The first two words I will label:
- ἐγερθεὶς: participle (aorist passive)
- ἆρόν: main verb (2nd person, aorist active imperative)
This usage of the participle is called "attendant circumstance." The participle describes an action that is a prerequisite for the action of the main verb. This is a fairly common use of the participle and is normally translated as a finite verb whose mood is derived from that of the main verb.2
Wallace offers five features for identifying an attendant circumstance construction (italics original):
- The tense of the participle is usually aorist.
- The tense of the main verb is usually aorist.
- The mood of the main verb is usually imperative or indicative.
- The participle will precede the main verb - both in word order and time of event (though usually there is very close proximity).
- Attendant circumstance participles occur frequently in narrative literature, infrequently elsewhere.
This passage meets all five criteria. Therefore, because the main verb is an imperative, the participle also carries imperatival force. The parallel in Mark (2:11) actually uses two imperatives:
A very similar attendant circumstance construction, also using ἐγερθεὶς followed by an aorist imperative, occurs in Matt 2:13, quoting the angel’s instructions to Joseph:
ἐγερθεὶς παράλαβε τὸ παιδίον καὶ τὴν μητέρα αὐτοῦ καὶ φεῦγε...(NA28)
"Rise, take the child and his mother, and flee..."(ESV)
Here, "rise" is a prerequisite to "take."
The only semi-plausible alternative would be to translate these as temporal adverbial clauses:
After rising, take the child... By omitting the imperative, that English could reasonably be read as,
After you decide to rise, whenever that might be, take the child... This is a bit sillier than it would be for the example in the question, but the point remains that both of these meet all of the syntactical criteria used to identify attendant circumstance participles, and both make considerably more sense that way.
1. Although I have a slight objection to the rendering in the question: "Arise!" Most translations are more like the ESV: "Rise, pick up..." This matters because the first verb is (semantically) dependent on the second, and the exclamation point (in my, admittedly subjective, view) interrupts that relationship.
2. Daniel B. Wallace, Greek Grammar Beyond the Basics: an Exegetical Syntax of the New Testament (Zondervan, 1996), pp 640-645. He doesn't discuss Matt 9:6 directly but does use 2:13 as an example, with the argument summarized here.