First thing I realize the homeworld will start at TL 9 and have a starport A to build starships. Unless the world is balkanized, there will probably be only one space program. The big this for an exploratory and colonization is conservation od resources.
The homeworld will be, by virtue of only Jump 1, only scouting the local Main, all the worlds connected by one parsec. The first explorer will be a 200 tonner. It won't be until TL 11 they discover Jump 2 engines will fit on 100 tons. Until the race reaches TL 11 decades or centuries away, the main cluster will have their most mature colonies. A 200 ton explorer will have the room as both explorer and surveyor gathering as much initial system and planetary data as possible before moving on. Once the main is surveyed, boards will analyze the information for which worlds offer the most potential for colonization establishing a priority of settlement. A world at the far end of a main might be far more attractive than three around the homeworld.
The predecessor to traders will be colony ships built to haul materials, equipment and colonists to establish the initial outpost which, hopefully, will grow to a colony and beyond. Some worlds may only need outposts to serve a function such as a small refueling port in a system with no other importance. Once an outpost is established, dedicated freighters will ferry more people and materials for growth and development. By the way, all these colonies will have the same TL as the home world. Differing TLs would only occur with maturing colonies that become research centers leading to breakthroughs or disasters that cause collapse.
Once colonies are well established, freighters will move resources and goods to and from the homeworld and colonies. Entrepreneurs can begin to build trading companies and trade vessels to take advantage of markets not served by the larger freight haulers such as luxury items. There would be no need for commercial vessels to carry hardpoints and weapons at these early stages unless some entrepreneurs somehow discover 'jumpcussing'.
Rather than planetary defenses, unless there is an actual outside threats, economy of force will have small squadrons of travelling security vessels that patrol the colonies making ports of call and presenting the flag plus reacting to unrest. These vessels carry 'marine' forces for both boarding and ground security. If the homeworld was originally balkanized, there may be colonies of different nations and incidences might call for higher states of security.