**Core Concept**
The question tests the understanding of vaccination schedules and the ability to administer multiple vaccines in a single visit, focusing on the principles of **immunization** and **vaccine administration**. In pediatric care, vaccines are crucial for preventing infectious diseases.

**Why the Correct Answer is Right**
Since the correct answer options are not provided, let's discuss the general principle: multiple vaccines can be given in a single visit, but it depends on the type of vaccine, the age of the child, and the specific vaccination schedule recommended. For a 9-month-old un-immunized child, vaccines such as **Measles**, **OPV (Oral Poliovirus Vaccine)**, and **DTaP (Diphtheria, Tetanus, and Pertussis)** could potentially be administered, considering the child's age and vaccination status.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details, we cannot determine why this option might be incorrect, but generally, incorrect options might include vaccines that are not recommended at the age of 9 months or vaccines that cannot be co-administered.
**Option B:** Similarly, without specifics, this option could be incorrect if it suggests a vaccine not due at 9 months or one that should not be given with other vaccines.
**Option C:** This could be incorrect for the same reasons as above, considering the age and potential interactions or recommendations against co-administration.
**Option D:** This option's correctness depends on the vaccine listed and whether it aligns with recommended vaccination schedules for a 9-month-old child.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the **Measles vaccine** can be given as early as 6 months in certain circumstances but is typically administered at 9 months in many vaccination schedules, especially in areas where measles is prevalent.

**Correct Answer:** Correct Answer: D. Measles.